Bump rubocop-rails from 2.3.0 to 2.3.1

Bumps [rubocop-rails](https://github.com/rubocop-hq/rubocop-rails) from 2.3.0 to 2.3.1.
- [Release notes](https://github.com/rubocop-hq/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.3.0...v2.3.1)

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

Gemfile.lock

@@ -189,7 +189,7 @@ GEM
       rainbow (>= 2.2.2, < 4.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 1.7)
-    rubocop-rails (2.3.0)
+    rubocop-rails (2.3.1)
       rack (>= 1.1)
       rubocop (>= 0.72.0)
     ruby-progressbar (1.10.1)