Bump rubocop-rails from 2.3.2 to 2.4.0 (#12532)

Bumps [rubocop-rails](https://github.com/rubocop-hq/rubocop-rails) from 2.3.2 to 2.4.0.
- [Release notes](https://github.com/rubocop-hq/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](https://github.com/rubocop-hq/rubocop-rails/compare/v2.3.2...v2.4.0)

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

Gemfile

@@ -135,7 +135,7 @@ group :development do
   gem 'letter_opener_web', '~> 1.3'
   gem 'memory_profiler'
   gem 'rubocop', '~> 0.76', require: false
-  gem 'rubocop-rails', '~> 2.3', require: false
+  gem 'rubocop-rails', '~> 2.4', require: false
   gem 'brakeman', '~> 4.7', require: false
   gem 'bundler-audit', '~> 0.6', require: false
 

Gemfile.lock

@@ -565,7 +565,7 @@ GEM
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.7)
-    rubocop-rails (2.3.2)
+    rubocop-rails (2.4.0)
       rack (>= 1.1)
       rubocop (>= 0.72.0)
     ruby-progressbar (1.10.1)
@@ -779,7 +779,7 @@ DEPENDENCIES
   rspec-rails (~> 3.9)
   rspec-sidekiq (~> 3.0)
   rubocop (~> 0.76)
-  rubocop-rails (~> 2.3)
+  rubocop-rails (~> 2.4)
   ruby-progressbar (~> 1.10)
   sanitize (~> 5.1)
   sidekiq (~> 5.2)