OSS CI for stacked commits

Pull Request resolved: #24

Make CI run for ghstacked commits, maybe?

Differential Revision: [D75176799](https://our.internmc.facebook.com/intern/diff/D75176799/)

**NOTE FOR REVIEWERS**: This PR has internal Meta-specific changes or comments, please review them on [Phabricator](https://our.internmc.facebook.com/intern/diff/D75176799/)!
ghstack-source-id: 285475797

Author: zdevito

.github/workflows/test.yml

@@ -7,6 +7,7 @@ on:
   pull_request:
     branches:
       - main
+      - gh/**
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref == 'refs/heads/main' && github.run_number || github.ref }}