Bump rubocop-rails from 2.23.1 to 2.24.0

Bumps [rubocop-rails](https://github.com/rubocop/rubocop-rails) from 2.23.1 to 2.24.0.
- [Release notes](https://github.com/rubocop/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.23.1...v2.24.0)

---
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

@@ -130,8 +130,7 @@ GEM
     dotenv-rails (3.1.0)
       dotenv (= 3.1.0)
       railties (>= 6.1)
-    drb (2.2.0)
-      ruby2_keywords
+    drb (2.2.1)
     em-websocket (0.5.3)
       eventmachine (>= 0.12.9)
       http_parser.rb (~> 0)
@@ -329,15 +328,14 @@ GEM
       rubocop-ast (>= 1.30.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 2.4.0, < 3.0)
-    rubocop-ast (1.30.0)
-      parser (>= 3.2.1.0)
-    rubocop-rails (2.23.1)
+    rubocop-ast (1.31.1)
+      parser (>= 3.3.0.4)
+    rubocop-rails (2.24.0)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
       rubocop (>= 1.33.0, < 2.0)
-      rubocop-ast (>= 1.30.0, < 2.0)
+      rubocop-ast (>= 1.31.1, < 2.0)
     ruby-progressbar (1.13.0)
-    ruby2_keywords (0.0.5)
     rubyzip (2.3.2)
     safe_yaml (1.0.5)
     sass-embedded (1.69.7)