Add new team member to slack message broker (#7217)

Author: zeme-wana

.github/workflows/slack-message-broker.yml

@@ -49,7 +49,8 @@ jobs:
                 "ana-pantilie": ["U05V2854W86"],
                 "zliu41": ["U03BP2HTKDK"],
                 "bezirg": ["UQ1LUSR8B"],
-                "erikd": ["U914V9D2B"]
+                "erikd": ["U914V9D2B"],
+                "SeungheonOh": ["U08RN7SACTT"]
               };
 
               const workflowOwners = {