chore: skip hermetic generation on fork PRs

.github/workflows/hermetic_library_generation.yaml

@@ -19,6 +19,8 @@ on:
 
 jobs:
   library_generation:
+    # skip pull requests come from a forked repository
+    if: github.event.pull_request.head.repo.full_name == github.repository
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v4