.github/workflows: fix check to skip integration test for PRs from forks

Check that the full name of the repo from pull request events matches
the repo from the GitHub context to ensure we are properly skipping
integration tests coming from forks.

Updates #cleanup

Signed-off-by: Mario Minardi <[email protected]>

Author: mpminardi

.github/workflows/test.yml

@@ -22,7 +22,7 @@ jobs:
     # the bot does not have credentials for the integration testing tailnet.
     # TODO(mpminardi): revisit / remove this if / when we give dependabot a tailnet for
     # testing with a smaller blast radius.
-    if: ${{ !github.event.repository.fork && github.actor != 'dependabot[bot]' }}
+    if: ${{ github.event.pull_request.head.repo.full_name == github.repository && github.actor != 'dependabot[bot]' }}
     name: ${{ matrix.os }} (${{ matrix.arch }}) (${{ matrix.credential-type }}) tailscale-${{ matrix.version }}
     strategy:
       fail-fast: false