ci(deps): bump peaceiris/actions-gh-pages from 2 to 4 (#1057)

Author: dependabot[bot]

.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
       env:
         PERSONAL_TOKEN: ${{ secrets.PERSONAL_ACCESS_TOKEN }}
         PUBLISH_BRANCH: gh-pages