Bump rubocop-minitest from 0.20.0 to 0.20.1 (#346)

Bumps [rubocop-minitest](https://github.com/rubocop/rubocop-minitest) from 0.20.0 to 0.20.1.
- [Release notes](https://github.com/rubocop/rubocop-minitest/releases)
- [Changelog](https://github.com/rubocop/rubocop-minitest/blob/master/CHANGELOG.md)
- [Commits](rubocop/rubocop-minitest@v0.20.0...v0.20.1)

---
updated-dependencies:
- dependency-name: rubocop-minitest
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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

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