Bump peaceiris/actions-gh-pages from 3 to 4 (#29)

Author: dependabot[bot]

.github/workflows/push.yml

@@ -28,7 +28,7 @@ jobs:
 
       # Deploy to gh-pages
       - name: Deploy to gh-pages
-        uses: peaceiris/actions-gh-pages@v3
+        uses: peaceiris/actions-gh-pages@v4
         with:
           github_token: ${{ secrets.GITHUB_TOKEN }}
           publish_dir: ./dist