devtools 2.2.1

• test() now sets the collation order to C before running, which matches
  the behavior of tests when run with R CMD check (#2121)

• New options("devtools.ellipsis_action") option added to control the action
  of ellipsis in devtools. This should be one of

  • rlang::abort - to emit an error if arguments are unused
  • rlang::warn - to emit a warning if arguments are unused
  • rlang::inform - to emit a message if arguments are unused
  • rlang::signal - to emit a message if arguments are unused
    Using rlang::signal will produce no output unless the custom condition is
    caught, so it is the best way to retain backwards compatibility with devtools
    behavior prior to 2.2.0.
    The default behavior was also changed to issue a
    warning rather than an error if any arguments are unused, as there are some
    cases where devtools does not need to install the package, so unused
    arguments are false positives (#2109).

• install() now throws an error when it fails, as intended (#2120)

• install() now again reloads and re-attaches packages if they were
  previously loaded (#2111).

• release() no longer calls the deprecated dr_devtools() (#2105)

• test() now explicitly passes stop_on_failure = FALSE to
  testthat::test_dir() (@jameslamb, #2099)