Upgrade ruby/setup-ruby v1.267.0 -> v1.268.0 (#2012)

See:
- https://github.com/ruby/setup-ruby/releases/tag/v1.268.0
- ruby/setup-ruby@v1.267.0...v1.268.0

Author: Picnic-DevPla-Bot

.github/workflows/deploy-website.yml

@@ -43,7 +43,7 @@ jobs:
         uses: actions/checkout@1af3b93b6815bc44a9784bd300feb67ff0d1eeb3 # v6.0.0
         with:
           persist-credentials: false
-      - uses: ruby/setup-ruby@d5126b9b3579e429dd52e51e68624dda2e05be25 # v1.267.0
+      - uses: ruby/setup-ruby@8aeb6ff8030dd539317f8e1769a044873b56ea71 # v1.268.0
         with:
           working-directory: ./website
           bundler-cache: true