Bump ruby/setup-ruby from 1.305.0 to 1.306.0 (#252)

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.305.0 to 1.306.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](ruby/setup-ruby@0cb964f...c4e5b13)

---
updated-dependencies:
- dependency-name: ruby/setup-ruby
  dependency-version: 1.306.0
  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]

.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@0cb964fd540e0a24c900370abf38a33466142735 # v1.305.0
+        uses: ruby/setup-ruby@c4e5b1316158f92e3d49443a9d58b31d25ac0f8f # v1.306.0
         with:
           ruby-version: ${{ matrix.ruby }}
           rubygems: latest