build(deps): 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](4a9ddd6f33...868b3f0884)

---
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/docs.yml

@@ -53,7 +53,7 @@ jobs:
         run: vale docs/
 
       - name: Install Ruby
-        uses: ruby/setup-ruby@4a9ddd6f338a97768b8006bf671dfbad383215f4 # v1.207.0
+        uses: ruby/setup-ruby@868b3f088412f139260f27f5b148179b9dd6b008 # v1.208.0
         with:
           bundler-cache: true
           working-directory: docs

.github/workflows/rubydoc.yml

@@ -43,7 +43,7 @@ jobs:
           persist-credentials: false
 
       - name: Install Ruby
-        uses: ruby/setup-ruby@4a9ddd6f338a97768b8006bf671dfbad383215f4 # v1.207.0
+        uses: ruby/setup-ruby@868b3f088412f139260f27f5b148179b9dd6b008 # v1.208.0
         with:
           bundler-cache: true
           working-directory: rubydoc