Bump ruby/setup-ruby from 1.207.0 to 1.208.0

Bumps [ruby/setup-ruby](https://github.com/ruby/setup-ruby) from 1.207.0 to 1.208.0.
- [Release notes](https://github.com/ruby/setup-ruby/releases)
- [Changelog](https://github.com/ruby/setup-ruby/blob/master/release.rb)
- [Commits](ruby/setup-ruby@4a9ddd6...868b3f0)

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

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

Author: dependabot[bot]

.github/workflows/rubocop.yml

@@ -10,7 +10,7 @@ jobs:
       fail-fast: false
     steps:
       - uses: actions/checkout@v4
-      - uses: ruby/setup-ruby@4a9ddd6f338a97768b8006bf671dfbad383215f4
+      - uses: ruby/setup-ruby@868b3f088412f139260f27f5b148179b9dd6b008
         with:
           ruby-version: 2.6
       - name: Install Code Scanning integration