Build(deps): Bump rubocop from 1.20.0 to 1.21.0 (#14331)

Bumps [rubocop](https://github.com/rubocop/rubocop) from 1.20.0 to 1.21.0.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop/rubocop/compare/v1.20.0...v1.21.0)

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

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

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

Gemfile.lock

@@ -287,7 +287,7 @@ GEM
     openssl-signature_algorithm (1.1.1)
       openssl (~> 2.0)
     optimist (3.0.1)
-    parallel (1.20.1)
+    parallel (1.21.0)
     parallel_tests (3.7.1)
       parallel
     parser (3.0.2.0)
@@ -385,7 +385,7 @@ GEM
       json-schema (~> 2.2)
       railties (>= 3.1, < 7.0)
     rtlit (0.0.5)
-    rubocop (1.20.0)
+    rubocop (1.21.0)
       parallel (~> 1.10)
       parser (>= 3.0.0.0)
       rainbow (>= 2.2.2, < 4.0)