Use major version tag for github-pages-deploy-action (#4342)

This slightly reduces workload as we don't need to make a new update for every new point release. This aligns to what we do for other GitHub actions.

.github/workflows/deploy-website.yaml

@@ -98,7 +98,7 @@ jobs:
       working-directory: docs/
 
     - name: Deploy Github Pages
-      uses: JamesIves/github-pages-deploy-action@4.1.7
+      uses: JamesIves/github-pages-deploy-action@v4
       with:
         branch: gh-pages
         folder: docs/_site/