actually checkout again

Author: lorenzwalthert

.github/workflows/benchmarking.yaml

@@ -31,7 +31,7 @@ jobs:
       - name: Ensure base branch is fetched
         if: ${{ github.event_name == 'pull_request' }}
         run: |
-          # git checkout -b $GITHUB_HEAD_REF
+          git checkout -b $GITHUB_HEAD_REF
           echo "$GITHUB_HEAD_REF"
           echo "$GITHUB_BASE_REF"
           git branch