chore: do not send notification for draft prs

Author: Alex Wang

.github/workflows/notify_slack.yml

@@ -4,7 +4,7 @@ on:
   issues:
     types: [opened, reopened]
   pull_request_target:
-    types: [opened, reopened]
+    types: [opened, reopened, ready_for_review]
 
 permissions: {}
 
@@ -26,7 +26,7 @@ jobs:
             }
 
       - name: Send pull request notification to Slack
-        if: github.event_name == 'pull_request_target'
+        if: github.event_name == 'pull_request_target' && github.event.pull_request.draft == false
         uses: slackapi/slack-github-action@03ea5433c137af7c0495bc0cad1af10403fc800c # v3.0.2
         with:
           webhook: ${{ secrets.SLACK_WEBHOOK_URL_PR }}