Try updating deploy-pages to v4

Author: edwardalee

.github/workflows/deploy.yml

@@ -47,6 +47,6 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v3
+        uses: actions/deploy-pages@v4
 
 # TODO: Deploy to some third-party place for preview?