Bump rubocop-rails from 2.21.1 to 2.21.2

Bumps [rubocop-rails](https://github.com/rubocop/rubocop-rails) from 2.21.1 to 2.21.2.
- [Release notes](https://github.com/rubocop/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.21.1...v2.21.2)

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

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -246,7 +246,7 @@ GEM
       parser (>= 3.2.1.0)
     rubocop-minitest (0.32.2)
       rubocop (>= 1.39, < 2.0)
-    rubocop-rails (2.21.1)
+    rubocop-rails (2.21.2)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
       rubocop (>= 1.33.0, < 2.0)