Fix variable reference in sonar.yaml

Author: SamBarker

.github/workflows/sonar.yaml

@@ -67,7 +67,7 @@ jobs:
           git remote add upstream ${{ github.event.repository.clone_url }}
           git fetch upstream
           git checkout -B ${{ fromJson(steps.get_pr_data.outputs.data).base.ref }} upstream/${{ fromJson(steps.get_pr_data.outputs.data).base.ref }}
-          git checkout "origin/${SANITIZED_HEAD_REF}"
+          git checkout "origin/${{env.SANITIZED_HEAD_REF}}"
           git clean -ffdx && git reset --hard HEAD
       - name: Set up QEMU
         uses: docker/setup-qemu-action@c7c53464625b32c7a7e944ae62b3e17d2b600130