[ci] Also notify compiler ready for review PRs (facebook#32371)

Similar to facebook#32344

Author: poteto

.github/workflows/compiler_discord_notify.yml

@@ -2,7 +2,7 @@ name: (Compiler) Discord Notify
 
 on:
   pull_request_target:
-    types: [opened]
+    types: [opened, ready_for_review]
     paths:
       - compiler/**
       - .github/workflows/compiler_**.yml