fix workflow

Author: yosupo06

.github/workflows/document.yml

@@ -28,7 +28,7 @@ jobs:
           mv ../document_ja generated/ &&
           mv ../document_en generated/
       - name: Publish to github pages
-        if: ${{ github.repository == "atcoder/ac-library" }}
+        if: ${{ github.repository == 'atcoder/ac-library' }}
         uses: peaceiris/actions-gh-pages@v3
         with:
           deploy_key: ${{ secrets.ACTIONS_DEPLOY_KEY }}