CI: upload-pages-artifact from v1 to v3, deploy-pages from v2 to v4 - needed because GitHub deprecated artifact v3.

Author: matthew-carroll

.github/workflows/deploy.yaml

@@ -28,7 +28,7 @@ jobs:
 
       # Zip and upload the static site.
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v1
+        uses: actions/upload-pages-artifact@v3
         with:
           path: ./build
 
@@ -49,4 +49,4 @@ jobs:
     steps:
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v2
+        uses: actions/deploy-pages@v4