[O] Try to fix github concurrency

Former-commit-id: 3a72378914

.github/workflows/generator.yml

@@ -5,6 +5,11 @@ on:
     branches: [ main ]
   workflow_dispatch:
 
+# One generator at a time
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   build:
     runs-on: ubuntu-latest