build(deps-dev): bump rubocop from 1.38.0 to 1.39.0 (Homebrew#501)

Bumps [rubocop](https://github.com/rubocop/rubocop) from 1.38.0 to 1.39.0.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v1.38.0...v1.39.0)

---
updated-dependencies:
- dependency-name: rubocop
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

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

Gemfile.lock

@@ -21,7 +21,7 @@ GEM
     rake (13.0.6)
     regexp_parser (2.6.0)
     rexml (3.2.5)
-    rubocop (1.38.0)
+    rubocop (1.39.0)
       json (~> 2.3)
       parallel (~> 1.10)
       parser (>= 3.1.2.1)