ci(github-actions): update env var used in doc publish actions

it has been changed since peaceiris/actions-gh-pages@3

Author: Lee-W

.github/workflows/docspublish.yml

@@ -31,8 +31,10 @@ 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
-        PUBLISH_DIR: ./site
+        personal_token: ${{ secrets.PERSONAL_ACCESS_TOKEN }}
+        publish_branch: gh-pages
+        publish_dir: ./site
+        user_name: "github-actions[bot]"
+        user_email: "github-actions[bot]@users.noreply.github.com"