fixup! ci: check if a PR can be backported

.github/workflows/pr.yml

@@ -36,14 +36,14 @@ jobs:
           # Find common ancestor between main and topic branch
           BRANCH_POINT=$(git merge-base $(git rev-parse --abbrev-ref HEAD) origin/main)
           [[ -z BRANCH_POINT ]] && echo "No branch point" && exit 1
-          echo "::set-output name=REF::$BRANCH_POINT"
+          echo "REF=$BRANCH_POINT" >> $GITHUB_OUTPUT"
       - name: Checkout libs maintenance branch
         uses: actions/checkout@v4
         with:
           ref: ${{ env.MAINT_LIBS_BRANCH }}
       - name: Backport PR to libs maintenance branch
         run: |
-          git cherry-pick --strategy=recursive --strategy-option=theirs ${{ steps.branch_point.outputs.REF }}..${{ github.event.pull_request.head.ref }}
+          git cherry-pick --strategy=recursive --strategy-option=theirs ${{ steps.branch_point.outputs.REF }}..${{ github.event.pull_request.head.sha }}
       - name: Instal cargo release  
         run: cargo binstall -y cargo-release
       - name: Install build deps