use correct ref

Author: kellertk

.github/workflows/tests-integ.yml

@@ -16,7 +16,7 @@ jobs:
         uses: actions/checkout@v5
         with:
           fetch-depth: 0
-          ref: ${{ github.ref_name }}
+          ref: ${{ github.event.pull_request.head.sha }}
           persist-credentials: false
       - name: Package
         run: |