Bump rubocop-rails from 2.21.2 to 2.22.1 in /web/backend

Bumps [rubocop-rails](https://github.com/rubocop/rubocop-rails) from 2.21.2 to 2.22.1.
- [Release notes](https://github.com/rubocop/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.21.2...v2.22.1)

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

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

web/backend/Gemfile.lock

@@ -226,7 +226,7 @@ GEM
       rubocop-ast (>= 1.28.1, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.29.0)
+    rubocop-ast (1.30.0)
       parser (>= 3.2.1.0)
     rubocop-capybara (2.19.0)
       rubocop (~> 1.41)
@@ -235,7 +235,7 @@ GEM
     rubocop-performance (1.19.1)
       rubocop (>= 1.7.0, < 2.0)
       rubocop-ast (>= 0.4.0)
-    rubocop-rails (2.21.2)
+    rubocop-rails (2.22.1)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
       rubocop (>= 1.33.0, < 2.0)