Bump rubocop-rails from 2.4.1 to 2.9.1 (#3607)

* Bump rubocop-rails from 2.4.1 to 2.9.1

Bumps [rubocop-rails](https://github.com/rubocop/rubocop-rails) from 2.4.1 to 2.9.1.
- [Release notes](https://github.com/rubocop/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.4.1...v2.9.1)

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

* update rubocop-rails gem

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Campbell Allen <campbell.allen@gmail.com>

.rubocop.yml

@@ -33,7 +33,7 @@ Metrics/MethodLength:
   Max: 12
 
 Rails/SkipsModelValidations:
-  Whitelist:
+  AllowedMethods:
   - update_all
   - update_column
   - touch

Gemfile.lock

@@ -270,8 +270,8 @@ GEM
       faraday
       faraday-panoptes (~> 0.3.0)
       jwt (~> 1.5.0)
-    parallel (1.20.1)
-    parser (3.0.1.1)
+    parallel (1.21.0)
+    parser (3.0.2.0)
       ast (~> 2.4.1)
     pg (0.21.0)
     pg_search (2.3.0)
@@ -372,9 +372,10 @@ GEM
     rubocop-performance (1.10.2)
       rubocop (>= 0.90.0, < 2.0)
       rubocop-ast (>= 0.4.0)
-    rubocop-rails (2.4.1)
+    rubocop-rails (2.9.1)
+      activesupport (>= 4.2.0)
       rack (>= 1.1)
-      rubocop (>= 0.72.0)
+      rubocop (>= 0.90.0, < 2.0)
     rubocop-rspec (1.43.2)
       rubocop (~> 0.87)
     ruby-progressbar (1.11.0)
@@ -438,7 +439,7 @@ GEM
       thread_safe (~> 0.1)
     uglifier (4.1.20)
       execjs (>= 0.3.0, < 3)
-    unicode-display_width (1.7.0)
+    unicode-display_width (1.8.0)
     versionist (2.0.1)
       activesupport (>= 3)
       railties (>= 3)