adding if statement to tailscale connect step

only trigger if it's not from a forked PR

Author: tobiasehlert

.github/workflows/codecov.yml

@@ -17,6 +17,7 @@ jobs:
           go-version-file: go.mod
 
       - name: Connect to Tailnet
+        if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository
         uses: tailscale/github-action@v2
         with:
           args: --accept-dns=true