update to upload-pages-artifact@v4

Author: steveklabnik

.github/workflows/deploy.yml

@@ -30,7 +30,7 @@ jobs:
       - name: Setup Pages
         uses: actions/configure-pages@v4
       - name: Upload artifact
-        uses: actions/upload-pages-artifact@v2
+        uses: actions/upload-pages-artifact@v3
         with:
           # Upload entire repository
           path: 'book'