chore: reenable apiary library generation (#21963)

Author: alicejli

.github/workflows/codegen.yaml

@@ -1,4 +1,7 @@
 on:
+  schedule:
+  # Runs at 12:30, 1:30 and 2:30.
+  - cron: '30 0-2 * * *'
   workflow_dispatch:
 
 name: codegen