update actions to use ruby 3.0

Author: maneesha

.github/workflows/build-website.yaml

@@ -23,7 +23,7 @@ jobs:
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: '2.7'
+          ruby-version: '3.0'
 
       - name: Install GitHub Pages, Bundler, and kramdown gems
         run: |