Update rubocop-minitest requirement from 0.32.2 to 0.33.0 (#12)

Updates the requirements on [rubocop-minitest](https://github.com/rubocop/rubocop-minitest) to permit the latest version.
- [Release notes](https://github.com/rubocop/rubocop-minitest/releases)
- [Changelog](https://github.com/rubocop/rubocop-minitest/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-minitest@v0.32.2...v0.33.0)

---
updated-dependencies:
- dependency-name: rubocop-minitest
  dependency-type: direct:production
...

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

Gemfile

@@ -5,7 +5,7 @@ gem "minitest", "~> 5.11"
 gem "minitest-reporters", "~> 1.3"
 gem "rake", "~> 13.0"
 gem "rubocop", "1.56.4"
-gem "rubocop-minitest", "0.32.2"
+gem "rubocop-minitest", "0.33.0"
 gem "rubocop-packaging", "0.5.2"
 gem "rubocop-performance", "1.19.1"
 gem "rubocop-rake", "0.6.0"