Bump ruby/setup-ruby from 1.320.0 to 1.321.0

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.320.0 to 1.321.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](ruby/setup-ruby@a30dfa4...95ef2b0)

---
updated-dependencies:
- dependency-name: ruby/setup-ruby
  dependency-version: 1.321.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

.github/workflows/rspec.yml

@@ -33,7 +33,7 @@ jobs:
       - run: rm -f Gemfile.lock
       - run: rm -f .ruby-version
       - name: Set up Ruby
-        uses: ruby/setup-ruby@a30dfa457ad68707b8b910ac3a244714b61c0626 # v1.320.0
+        uses: ruby/setup-ruby@95ef2b042f9d7a56d8268cba8559e2842e2ad01b # v1.321.0
         with:
           ruby-version: ${{ matrix.ruby }}
           rubygems: latest