update ruby version in CI

Author: gasparnagy

.github/workflows/jekyll.yml

@@ -31,7 +31,7 @@ jobs:
         # https://github.com/ruby/setup-ruby/releases/tag/v1.207.0
         uses: ruby/setup-ruby@4a9ddd6f338a97768b8006bf671dfbad383215f4
         with:
-          ruby-version: '3.1' # Not needed with a .ruby-version file
+          ruby-version: '3.3' # 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