Bump rubocop-rails from 2.21.1 to 2.22.0

Bumps [rubocop-rails](https://github.com/rubocop/rubocop-rails) from 2.21.1 to 2.22.0.
- [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...v2.22.0)

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

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

Gemfile.lock

@@ -229,7 +229,7 @@ GEM
       multi_json
     orm_adapter (0.5.0)
     parallel (1.23.0)
-    parser (3.2.2.3)
+    parser (3.2.2.4)
       ast (~> 2.4.1)
       racc
     pathutil (0.16.2)
@@ -283,7 +283,7 @@ GEM
       redis-client (>= 0.9.0)
     redis-client (0.17.0)
       connection_pool
-    regexp_parser (2.8.1)
+    regexp_parser (2.8.2)
     request_store (1.5.1)
       rack (>= 1.4)
     responders (3.1.0)
@@ -303,9 +303,9 @@ 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-rails (2.21.1)
+    rubocop-rails (2.22.0)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
       rubocop (>= 1.33.0, < 2.0)
@@ -361,7 +361,7 @@ GEM
       concurrent-ruby (~> 1.0)
     uglifier (4.2.0)
       execjs (>= 0.3.0, < 3)
-    unicode-display_width (2.4.2)
+    unicode-display_width (2.5.0)
     vcr (6.2.0)
     warden (1.2.9)
       rack (>= 2.0.9)