Update main.yml

Author: JakeChampion

.github/workflows/main.yml

@@ -384,6 +384,7 @@ jobs:
     - uses: actions/checkout@v3
       with:
         submodules: false
+        ref: ${{ github.head_ref || github.ref_name }}
     - uses: ./.github/actions/e2e
       with:
         fastly-api-token: ${{ secrets.FASTLY_API_TOKEN }}