fix: prefer using fromJson with outputs for branch name

.github/workflows/conventional-commit-release.yaml

@@ -240,9 +240,7 @@ jobs:
         id: checkout-release-branch
         uses: actions/[email protected]
         with:
-          # the branch name will always follow this pattern
-          # https://github.com/googleapis/release-please/blob/439290c63c5790d9161396fdba1daca4b8781e44/src/util/branch-name.ts#L211
-          ref: "release-please--branches--${{ github.ref_name }}--components--${{ github.event.repository.name }}"
+          ref: ${{ fromJson(steps.release.outputs.pr).headBranchName }}
           fetch-depth: 0
 
       - name: Import GPG key