chore: do not send notification for draft PR

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: {}
 
@@ -14,7 +14,7 @@ jobs:
     steps:
       - name: Send issue notification to Slack
         if: github.event_name == 'issues'
-        uses: slackapi/slack-github-action@af78098f536edbc4de71162a307590698245be95 # v3.0.1
+        uses: slackapi/slack-github-action@45a88b9581bfab2566dc881e2cd66d334e621e2c # v3.0.3
         with:
           webhook: ${{ secrets.SLACK_WEBHOOK_URL_ISSUE }}
           webhook-type: incoming-webhook
@@ -26,8 +26,8 @@ jobs:
             }
 
       - name: Send pull request notification to Slack
-        if: github.event_name == 'pull_request_target'
-        uses: slackapi/slack-github-action@af78098f536edbc4de71162a307590698245be95 # v3.0.1
+        if: github.event_name == 'pull_request_target' && github.event.pull_request.draft == false
+        uses: slackapi/slack-github-action@45a88b9581bfab2566dc881e2cd66d334e621e2c # v3.0.3
         with:
           webhook: ${{ secrets.SLACK_WEBHOOK_URL_PR }}
           webhook-type: incoming-webhook