ci: push benchmark data to gh-pages

The action wrote results to a local gh-pages branch and never pushed them. The next step then failed because docs/bench does not exist on main. The action now pushes gh-pages itself, and the manual push step is gone.

.github/workflows/release.yaml

@@ -59,19 +59,9 @@ jobs:
           github-token: ${{ secrets.GITHUB_TOKEN }}
           comment-on-alert: true
           summary-always: true
-          auto-push: false
+          auto-push: true
           benchmark-data-dir-path: "docs/bench"
 
-      - name: Push benchmark results
-        env:
-          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
-        run: |
-          git config user.name "github-actions[bot]"
-          git config user.email "github-actions[bot]@users.noreply.github.com"
-          git add docs/bench
-          git diff --staged --quiet || git commit -m "Update benchmark results"
-          git push origin main
-
   publish-helm-chart:
     name: Publish Helm Chart
     needs: release