Bump rubocop from 0.91.0 to 0.91.1

Bumps [rubocop](https://github.com/rubocop-hq/rubocop) from 0.91.0 to 0.91.1.
- [Release notes](https://github.com/rubocop-hq/rubocop/releases)
- [Changelog](https://github.com/rubocop-hq/rubocop/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop@v0.91.0...v0.91.1)

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

Gemfile.lock

@@ -390,7 +390,7 @@ GEM
     rexml (3.2.4)
     rinku (2.0.6)
     rotp (6.1.0)
-    rubocop (0.91.0)
+    rubocop (0.91.1)
       parallel (~> 1.10)
       parser (>= 2.7.1.1)
       rainbow (>= 2.2.2, < 4.0)