Use Ubuntu's latest image for GitHub actions (#348)

See actions/runner-images#11101

Author: seanprashad

.github/workflows/github-pages.yml

@@ -14,7 +14,7 @@ on:
 
 jobs:
   build-and-deploy:
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-latest
     steps:
       - name: Checkout Repository
         uses: actions/checkout@v3