ci(github-actions): update peaceiris/actions-gh-pages to v4

Author: Lee-W

.github/workflows/docspublish.yml

@@ -31,7 +31,7 @@ jobs:
           token: ${{ secrets.PERSONAL_ACCESS_TOKEN_FOR_ORG }}
           file: "docs/README.md"
       - name: Push doc to Github Page
-        uses: peaceiris/actions-gh-pages@v2
+        uses: peaceiris/actions-gh-pages@v4
         with:
           personal_token: ${{ secrets.PERSONAL_ACCESS_TOKEN }}
           publish_branch: gh-pages