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] <support@github.com>

Gemfile.lock

@@ -113,8 +113,7 @@ GEM
     dotenv-rails (2.8.1)
       dotenv (= 2.8.1)
       railties (>= 3.2)
-    drb (2.2.0)
-      ruby2_keywords
+    drb (2.2.1)
     erubi (1.12.0)
     et-orbi (1.2.7)
       tzinfo
@@ -162,7 +161,7 @@ GEM
     marcel (1.0.2)
     matrix (0.4.2)
     mini_mime (1.1.5)
-    minitest (5.21.2)
+    minitest (5.22.2)
     mqtt (0.6.0)
     msgpack (1.7.2)
     mutex_m (0.2.0)
@@ -198,7 +197,7 @@ GEM
       nio4r (~> 2.0)
     raabro (1.4.0)
     racc (1.7.3)
-    rack (3.0.8)
+    rack (3.0.9.1)
     rack-session (2.0.0)
       rack (>= 3.0.0)
     rack-test (2.1.0)
@@ -258,8 +257,8 @@ 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-ast (1.31.1)
+      parser (>= 3.3.0.4)
     rubocop-capybara (2.20.0)
       rubocop (~> 1.41)
     rubocop-minitest (0.34.5)
@@ -268,13 +267,12 @@ GEM
     rubocop-performance (1.20.2)
       rubocop (>= 1.48.1, < 2.0)
       rubocop-ast (>= 1.30.0, < 2.0)
-    rubocop-rails (2.23.1)
+    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)
     rufus-scheduler (3.9.1)
       fugit (~> 1.1, >= 1.1.6)