workflow: downgrade ruby to 3.1 to work with bundle

Author: stffrdhrn

.github/workflows/pages.yml

@@ -33,9 +33,9 @@ jobs:
       - name: Checkout
         uses: actions/checkout@v4
       - name: Setup Ruby
-        uses: ruby/setup-ruby@v1
+        uses: ruby/setup-ruby@4a9ddd6f338a97768b8006bf671dfbad383215f4
         with:
-          ruby-version: '3.3' # Not needed with a .ruby-version file
+          ruby-version: '3.1' # Not needed with a .ruby-version file
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically
           cache-version: 0 # Increment this number if you need to re-download cached gems
       - name: Setup Pages