No duplicate runs for internal PRs

Author: Technici4n

.github/workflows/CI.yaml

@@ -16,6 +16,9 @@ concurrency:
 
 jobs:
     test:
+        # Only run the pull-request build if the pull-request was opened from another repository,
+        # since we already run this workflow for the branch the pull request was made from.
+        if: github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name != github.repository
         runs-on: ubuntu-latest
         steps:
             - name: Checkout this repository