deploy branch specific docs

Author: mmsaki

.github/workflows/docs.yml

@@ -42,8 +42,25 @@ jobs:
 
       - name: Deploy to GitHub Pages
         uses: peaceiris/actions-gh-pages@v3
-        with:
-          github_token: ${{ secrets.GITHUB_TOKEN }}
-          publish_dir: ./docs/book
-          publish_branch: gh-pages
-          force_orphan: true
+        run: |
+          git config user.name "github-actions[bot]"
+          git config user.email "github-actions[bot]@users.noreply.github.com"
+
+          BRANCH_NAME=${GITHUB_REF#refs/heads/}
+          SAFE_BRANCH_NAME=$(echo "$BRANCH_NAME" | tr '/' '-')
+
+          git clone --depth=1 --branch gh-pages https://github.com/${{ github.repository }} gh-pages || \
+          git clone --depth=1 https://github.com/${{ github.repository }} gh-pages && \
+          cd gh-pages && \
+          git checkout --orphan gh-pages
+
+          cd gh-pages
+
+          rm -rf "$SAFE_BRANCH_NAME"
+          mkdir -p "$SAFE_BRANCH_NAME"
+
+          cp -r ../docs/book/* "$SAFE_BRANCH_NAME/"
+
+          git add "$SAFE_BRANCH_NAME"
+          git commit -m "Update docs for branch $BRANCH_NAME" || echo "No changes to commit"
+          git push origin gh-pages