Update jekyll.yml

Added "Setup Ruby" step

Author: jonblower

.github/workflows/jekyll.yml

@@ -33,6 +33,12 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v4
+      - name: Setup Ruby
+        uses: ruby/setup-ruby@8575951200e472d5f2d95c625da0c7bec8217c42 # v1.161.0
+        with:
+          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
         id: pages
         uses: actions/configure-pages@v5