ci: skip droplet integration matrix for external fork PRs

Author: benvinegar

.github/workflows/integration.yml

@@ -57,7 +57,7 @@ jobs:
 
   integration:
     needs: [docs-scope]
-    if: needs.docs-scope.outputs.docs_only != 'true'
+    if: needs.docs-scope.outputs.docs_only != 'true' && (github.event_name != 'pull_request' || github.event.pull_request.head.repo.full_name == github.repository)
     runs-on: *default-runner
     strategy:
       fail-fast: false