Bump rubocop-rails from 2.12.4 to 2.13.0 in /.overcommit

Bumps [rubocop-rails](https://github.com/rubocop/rubocop-rails) from 2.12.4 to 2.13.0.
- [Release notes](https://github.com/rubocop/rubocop-rails/releases)
- [Changelog](https://github.com/rubocop/rubocop-rails/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-rails@v2.12.4...v2.13.0)

---
updated-dependencies:
- dependency-name: rubocop-rails
  dependency-type: indirect
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

.overcommit/Gemfile.lock

@@ -38,21 +38,21 @@ GEM
     rainbow (3.0.0)
     regexp_parser (2.2.0)
     rexml (3.2.5)
-    rubocop (1.23.0)
+    rubocop (1.24.0)
       parallel (~> 1.10)
       parser (>= 3.0.0.0)
       rainbow (>= 2.2.2, < 4.0)
       regexp_parser (>= 1.8, < 3.0)
       rexml
-      rubocop-ast (>= 1.12.0, < 2.0)
+      rubocop-ast (>= 1.15.0, < 2.0)
       ruby-progressbar (~> 1.7)
       unicode-display_width (>= 1.4.0, < 3.0)
     rubocop-ast (1.15.0)
       parser (>= 3.0.1.1)
     rubocop-performance (1.12.0)
       rubocop (>= 1.7.0, < 2.0)
       rubocop-ast (>= 0.4.0)
-    rubocop-rails (2.12.4)
+    rubocop-rails (2.13.0)
       activesupport (>= 4.2.0)
       rack (>= 1.1)
       rubocop (>= 1.7.0, < 2.0)