Fix branch ref in CI

Author: cowtowncoder

.github/workflows/main.yml

@@ -82,7 +82,7 @@ jobs:
     name: Trigger downstream builds
     needs: [build]
     # Only for pushes to default branch
-    if: ${{ github.event_name == 'push' && github.event.ref_name == github.event.repository.default_branch }}
+    if: ${{ github.event_name == 'push' && github.ref_name == github.event.repository.default_branch }}
     uses: ./.github/workflows/trigger_dep_builds.yml
     secrets:
       token: ${{ secrets.REPO_DISPATCH }}