ci: update gh pages action

Author: ctron

.github/workflows/pages.yaml

@@ -47,7 +47,7 @@ jobs:
           find ./site/public
 
       - name: Deploy
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./site/public