Update dependency bazelbuild/buildtools to latest version

Included changes:

  - e4230a839458e17325c0718f2e77b706445d0b8f Add/replace license headers (#882)
  - 80af3a07e4fee8bc56e4ccc1f203fa955a577b44 Automatically remove superfluous parens (#884)
  - 8a6c6c3b7d39bc3bad605b2e8ec5b80616eeb6fd license: update lic to apache 2.0 (#872)
  - f76b57a9805f2096426f8668a363ae6ccae473ec Add warning for calls to `provider` without `doc` or `fie...
  - b1667ff58f714d13c2bba6823d6c52214705508f Get rid of the shift/reduce conflicts in the yacc grammar...
  - 7141127cf9d8db23c9fea5e086466acbf461a66d Decree package_group.packages as a non-label attribute (#...
  - ce0cf814cb03dddf546ea92b3d6bafddb0b9eaf8 Have .star files detected as Starlark (#869)
  - c6dbed2cac5a04672c50ca8c74c97a811e6b8ae9 Make disabling comments also disable warnings for comment...
  - b7c3f46ff700421e904cce0a339f6a39d53d623a Enable buildifier warnings on the CI (#844)
  - 5db5097f13dc7097e31c8031f6f7b4ec5193a697 Address linter warnings (#868)
  - a60df6e5d134ed103669f206ad74ec2154f1a562 Dont warn about disabling comments (#866)
  - 5d5be7b7032708a8acdec57e29c1f274449bd1c5 Fix potential NPE (#864)
  - 4b11e3f608a9cef8a221ccb5e1e466cc46d0e166 Don't warn about using "skylark" inside URLs (#863)
  - f540e7b9a59cd01298d5e6aa87b5a488a717e07d Don't recognize native.package_name() as a rule (#862)
  - d8ba0a6d2ed24aa7ae68d54412db84eb7dfe6192 Fix the definition of lambda expressions (#860)
  - d80f53c8af51a9cabfe286464a7d198509edcd45 Add tests for lambdas and sets (#859)
  - bcd428a8b48ef44671004b3c1b1f2c4715fc4d2c Support float numbers (#858)
  - a6c28d6bd15cfc11cc8d6d99a5a6f7352398ccc6 Fix dict nodes traversal (#857)
  - b0c5f0506cff8c64525382d19f1e00be4657499f Restrict dict elements to KeyValueExpr objects (#856)
  - 1b8e4fc961966f7cd29b334cfd5eb2265fd194e0 Fix working with comments inside select statememnts (#855)
  - 720b9d5a89d3931a46e00d34f2c200b3d4adce51 Make buildozer replace values inside select statements (#...
  - 59fe86744ed0b246e8cb0ed94604b3e60dc72d1a Fix windows handling of path to build file containing "/"...
  - 35db43bc5bf30a158ea1d2775402f51fac7865f1 support floats in buildifier2 (#851)
  - 8de190500912105ad59bdb5e65458dcc9df23256 Fix a typo (#850)
  - 6ef6a5f7f1caf09f77876267c5427e620f853dac Fix file format (#848)
  - f4e8394f069d501c96d5e14adfc6cb34569bbd08 Add comments for golint (#847)
  - fbd908424999c721361c3bd63da5dde00a53cabf Fix nil nodes traversal (#846)
  - fdda33f69e024e40378f208c871a53b7b48e3558 Make the parameter 'bin' public (#845)
  - 532ebdbbcc1a5162aede79f74e7ac6d9e18198a3 Fix the docstring location (#843)
  - c089ea97796d9eb411d68309de84cf009214ad18 Change generate_tables from genrule to .bzl rule. (#842)
  - 3cae0ce55c70b165c628a776bf79e0fe8139ff52 Replace genrule in go_yacc with custom bzl rule. (#841)
  - f32d930a37d8e2ba3a869406f65a800073eb3e2f Export build file names variables (#836) (#838)
  - 7d8bb10b5dcd38ab2f45041a5a7cd3a284621d51 Implement a warning for the word 'skylark' in comments an...
  - c98e381e8651e97d6da52122b288ec2ba6c392ec Export build file names variables (#836)
  - 3f91ca4d95ecad21109a41924b19502e272ceaf8 Clarify unnamed macro warning (#829)
  - 6c962bebb93ae4560c2257221fb14b3c3d2ec39f Allow quoted arguments in buildozer's replace command (#8...
  - 8b5120148af9394db373931edff01db574c96d5b Correctly parse docstrings in CRLF-formatted files (#826)
  - daa2a2cfc23c13d3e893644d6015c54c77738be6 Fix SortableWhitelist (#827)
  - 3b3222d629fa408bffc5eb94f45ae7a61714d3db Don't apply unnamed-macro to private functions (#825)
  - 2d1e6f121721cbf1dfa082dff5826a1c516260dd Authomatise GitHub release process (#822)
  - dbd4ef8997abb3a7bef0ba4867caaf206db86b6e Fixes for resolving import errors (#819)
  - ebfbc8d55dca9896b0ac6d6cd6a4418b7aabed97 Fix file packages (#818)
  - c137a33e2f877d32a1cb2f5f7933be1207bc63f1 feat: allow flags to be passed to buildozer via the NodeJ...
  - ccca1600e6678ef2410fc5eca7647cdeadce01a0 Implement the unnamed macro warning (#814)
  - acc1c735b7aedc53fc089d09ca22ba5254975351 Refactor rewrites (#815)
  - 39e438388635b4569596954035260832c34a6adc Remove string-escape from warnings, this option is no lon...
  - 6827138c86919697c98133b84678b9176225ba8f Add buildifier warning on deprecated use of the 'items' p...
  - c8b914a8e899dfce4f774bf2c531a78797ebd628 Implement deprecated function warning (#807)
  - 22e56e7356b839fca53d4d20aff02e1a0dce32ae Fix missing files in npm distribution (#804)
  - 9b46ce3ad64887aa509aea8d32edfd6a10ebaa9d Mute false positive warnings for private .bzl files (#803)
  - 5ea03ef960faceeb0220b6cb36af17e974b2de1d add nodejs binding to conveniently use buildozer from a n...
  - 2797858400171ffaa3074c22925b05ed54b634f1 Move npm rules to separate packages (#800)
  - c9d9e342afdb4c5a50af58535c470836e00d863a fix(buildifier): add rules_nodejs to //buildifier:deps.bz...
  - e4857a0a3c8c14a1b706923b13e87b7fe5dc3829 Allow any characters in string literals to be escaped as ...
  - ad1228dbe56d3b0073415437b94d88598d9c95d5 Enable bzl-visibilty warnings by default (#795)
  - 66444f75b6cf80f48949ec366c61a6117b895e98 Format WORKSPACE and BUILD.bazel files with buildifier (#...
  - 704f17c055ef5d90b3a615c2c69e86411761ea70 Fix .bzl visibility warnings (#792)
  - d6c9db8d886e48acf16cb79649b40a8dd06b3cd4 Fix the workspace root detection (#791)
  - 98244f725d46ab37614ac6bbb653a6827a46fabd Add publishing to npm (#787)
  - e1f68e814c4157b76225d59d7003cda2619f988b Opensource buildozer tests (#788)
  - 90de5e7001fbdfec29d4128bb508e01169f46950 Add multiplatform build targets (#786)
  - cabcfb469f104d032feb6267e48e75e71e78ff73 buildozer: Add command substitute_load (#781)
  - 5b955d36dcf931648f168381a40dab874ddf9072 Disallow implicit string literal concatentation (#784)
  - f3a7ff6345728d40c481edae1d283f1657e7bda7 Fix escape sequences in string literals (#783)
  - 937c718b9c2725f3dfcb2ba86a84d25826468969 buildozer: Add example for new replace_load command (#780)
  - b0fd03a9fe4074c3e956d1d807b143cbd4514e14 buildozer: Add command replace_load (#779)
  - 9e63c6f02e63adaab63e21a3a8feb75f4f7503cb Allow escaped linebreaks in buildozer command arguments (...
  - f630fda6c1db92241fee1ff66ca07018b2c7a5f3 Don't warn about undocumented * (#775)
  - e002736a9eca26c3356590213bff9292ca4af580 Update the skylark_syntax repo (#777)
  - 62c765f25028c0e952ba49d73613c96cbef15757 Allow buildozer arguments to be joined with newlines (#773)
  - e38eae7ee590ca3bb894c44751f79b8f68a9bbf2 Improve the warning message for missing argument document...
  - 3527f4e21874689a86d7e138c8997b8a4c9e3e75 Make buildtools compatible with future releases of Bazel ...
  - af594acc14f88c13f8fafa8bae4971a77f66a4fe Don't use tables.NamePriority for sorting dict items (#769)
  - 41a45edb9184de83dd29e2791bd995fbb73ea141 Fix string quoting (#767)
  - fb276b37173c37b38ce1ac35a1753950ccd66a10 Improve the warning message if no documented args are fou...
  - de8e1ba7d8d9fc5a79e658bb79f1c1f881a8180b fix order dependency by adding a defer to Chdir back to t...
  - d5d5c58c9e32e6cc65500cbe4429451ba942fe1a Replace the string-escape check with mandatory reformatti...
  - 406053e3dd00272cca614faa238736fc4dec6178 Add "disable" keywords for better docs search (#749)
  - 56b711bcbcb6ee98bdbf94c830beaeaf030676a7 Add syntax highlighting to the warnings file (#752)
  - 77355e5628b4bfffa932bc8645ea165d9f5c486d Don't reformat raw string literals (#747)
  - e1746d65f6ddd467655b28aa9471646ab2cafda3 Implement list-append warning and fix (#743)
  - 195b83e94906df245fdc44da27b1be5489087025 Remove legacy DisableLoadSortForBuildFiles (#742)
  - f56caf5225ac6bbb1cb3b62c498c1b9ec36e5da5 Fix parser for adding to dictionary. (#739)
  - 2ff34e8cd60f6c5c25f029ed0aa347f18d086bef Print an empty line after statements with after-comments ...
  - 9f3978593d3ee017a9badc0adde9c552390cf7bf Fix targetExpressionToBuildFiles (#738)
  - 7e793330b31d465f6bffe101ace2ab25d75e2eec Fix golint warnings (#736)
  - 2bbf3160364118e3518391ced7b3c3f55b2a3a84 Don't run rule warnings functions on WORKSPACE files (#734)
  - befae06063da26e7bd67ca49495d687a390eb824 buildozer: Add command for appending to lists in a dict a...
  - 19db42aa7a206a52b67bc66477c069ca83d092f4 Fix recursive traversal of BUILD files for "..." targets ...
  - a795ddbeaffc5da41777361f1930ab701c04f996 unused_deps: Support BUILD.bazel files (#728)
  - 89ce10de6b39666331d0d91c0d7e5a146a920cef Enable 'load-on-top' for BUILD files (#725)
  - 95fa97a84a86f84c901e5d7abfce224f6f92d6f2 Disable the checks for positional and keyword arguments f...
  - 69366ca98f89fc33ea5ca797498a65261de91e63 Make the bzl-visibility check non-default (#721)
  - 9cee1d97b654057bc4819dce1109f0c25cda6c21 Allow string escapes for raw strings (#720)
  - 5244fa10df2befc43057d7de19d2c79c4c88639a Update new_rule doc to new (#719)
  - 5bcc31df55ec1de770cb52887f2e989e7068301f buildifier: Add additional patterns in runner.bash.templa...
  - aef5cc1e9c5bdb8c42473b4a974e9c38d54cc088 Fix AddValueToList (#715)
  - a3b05f3d9cc5b708b6f53199d637525e108633f0 Fix .bzl format (#714)
  - 98dd4a65c09f0cd6aa048316eb8358ee1181c6d1 Fix ResolveAttr (#713)
  - f8b2ce4ca484e24bddd22d1eca9c5746cfd4bf4c Add additional file patterns (#712)
  (And 476 more changes)

BAZEL_BUILDTOOLS_VERSION_REV_ID: e4230a839458e17325c0718f2e77b706445d0b8f
Change-Id: Ibdf2f1299ef8a2d7694d8768f399857b049edb07

third_party/bazel_buildtools.bzl

@@ -0,0 +1,19 @@
+# Copyright 2019 Google Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+# This file is autogenerated by copybara, please do not edit.
+
+buildtools_version = "e4230a839458e17325c0718f2e77b706445d0b8f"
+buildtools_sha256 = "15a91aebc241387926272d3add7379f3a50155e890c3b9e026d9433557add705"