restore library generation

Author: diegomarquezp

.github/workflows/hermetic_library_generation.yaml

@@ -15,9 +15,7 @@
 # downstream client libraries before they are released.
 name: Hermetic library generation upon generation config change through pull requests
 on:
-  # TODO: uncomment this before merging to prevent a formatting regression
-  #pull_request:
-  workflow_dispatch:
+  pull_request:
 
 env:
   REPO_FULL_NAME: ${{ github.event.pull_request.head.repo.full_name }}