INFRA-3187: Update ref for testing

Author: XxdpavelxX

.github/workflows/merge-previous-releases.yml

@@ -33,6 +33,7 @@ jobs:
         uses: actions/checkout@v5
         with:
           repository: metamask/github-tools
+          ref: INFRA-3187-AutomateMergingReleaseBranches
           path: ./github-tools
 
       - name: Set Git user and email