Bump ruby/setup-ruby from 1.204.0 to 1.206.0

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.204.0 to 1.206.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](ruby/setup-ruby@401c19e...bfefad8)

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

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

.github/workflows/ci.yml

@@ -16,7 +16,7 @@ jobs:
       - name: Update .ruby-version with matrix value
         run: echo "${{ matrix.ruby_version }}" >| .ruby-version
       - name: Set up Ruby
-        uses: ruby/setup-ruby@401c19e14f474b54450cd3905bb8b86e2c8509cf
+        uses: ruby/setup-ruby@bfefad842bb982ff05b233bcbc1571d97a87e69f
         with:
           bundler-cache: true
       - name: Run tests