Bump rubocop-minitest from 0.27.0 to 0.28.0 (#254)

Bumps [rubocop-minitest](https://github.com/rubocop/rubocop-minitest) from 0.27.0 to 0.28.0.
- [Release notes](https://github.com/rubocop/rubocop-minitest/releases)
- [Changelog](https://github.com/rubocop/rubocop-minitest/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-minitest@v0.27.0...v0.28.0)

---
updated-dependencies:
- dependency-name: rubocop-minitest
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Gemfile.lock

@@ -65,8 +65,8 @@ GEM
       unicode-display_width (>= 2.4.0, < 3.0)
     rubocop-ast (1.26.0)
       parser (>= 3.2.1.0)
-    rubocop-minitest (0.27.0)
-      rubocop (>= 0.90, < 2.0)
+    rubocop-minitest (0.28.0)
+      rubocop (>= 1.39, < 2.0)
     rubocop-rake (0.6.0)
       rubocop (~> 1.0)
     ruby-progressbar (1.11.0)