Bump rexml from 3.2.8 to 3.3.9 in /.template (#529)

Bumps [rexml](https://github.com/ruby/rexml) from 3.2.8 to 3.3.9.
- [Release notes](https://github.com/ruby/rexml/releases)
- [Changelog](https://github.com/ruby/rexml/blob/master/NEWS.md)
- [Commits](ruby/rexml@v3.2.8...v3.3.9)

---
updated-dependencies:
- dependency-name: rexml
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

.template/Gemfile.lock

@@ -21,8 +21,7 @@ GEM
     racc (1.7.1)
     rainbow (3.1.1)
     regexp_parser (2.8.1)
-    rexml (3.2.8)
-      strscan (>= 3.0.9)
+    rexml (3.3.9)
     rspec (3.12.0)
       rspec-core (~> 3.12.0)
       rspec-expectations (~> 3.12.0)
@@ -66,7 +65,6 @@ GEM
       net-ssh (>= 2.7)
       net-telnet (= 0.1.1)
       sfl
-    strscan (3.1.0)
     unicode-display_width (2.4.2)
 
 PLATFORMS