Merge branch 'untrusted_co' of https://github.com/GitHubSecurityLab/codeql-actions into untrusted_co

Author: Alvaro Muñoz

ql/test/query-tests/Security/CWE-829/.github/workflows/auto_ci.yml

@@ -68,7 +68,7 @@ jobs:
         uses: actions/checkout@v3
         with:
           fetch-depth: 0
-          ref: ${{ github.event.pull_request.head.ref }}
+          ref: ${{ github.event.pull_request.head.ref || github.event.pull_request.base.ref }}
           repository: ${{ github.event.pull_request.head.repo.full_name }}
 
       - name: Set up Python ${{ matrix.python-version }}