fixed doc path for deployment

.github/workflows/docs.yml

@@ -17,10 +17,10 @@ jobs:
     - name: build doc
       run: make docs
     - name: deploy
-      uses: peaceiris/actions-gh-pages@v3
+      uses: peaceiris/actions-gh-pages@v4
       with:
         github_token: ${{ secrets.GITHUB_TOKEN }}
-        publish_dir: ./docs/html/
+        publish_dir: ./doc/html/
         enable_jekyll: false
         allow_empty_commit: false
         force_orphan: true