Bump rubocop from 1.12.1 to 1.13.0

Bumps [rubocop](https://github.com/rubocop/rubocop) from 1.12.1 to 1.13.0.
- [Release notes](https://github.com/rubocop/rubocop/releases)
- [Changelog](https://github.com/rubocop/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v1.12.1...v1.13.0)

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

Gemfile.lock

@@ -54,7 +54,7 @@ GEM
       activesupport (>= 5.0.0)
       hashie (>= 2.0.5)
       sengiri_yaml (>= 0.0.2)
-    rubocop (1.12.1)
+    rubocop (1.13.0)
       parallel (~> 1.10)
       parser (>= 3.0.0.0)
       rainbow (>= 2.2.2, < 4.0)