Fix #889 by correcting the team_join event handler

Author: seratch

tutorial/03-responding-to-slack-events.md

@@ -117,7 +117,7 @@ def onboarding_message(payload):
     user_id = event.get("user", {}).get("id")
 
     # Open a DM with the new user.
-    response = slack_web_client.im_open(user_id)
+    response = slack_web_client.conversations_open(users=user_id)
     channel = response["channel"]["id"]
 
     # Post the onboarding message.

tutorial/PythOnBoardingBot/app.py

@@ -52,7 +52,7 @@ def onboarding_message(payload):
     user_id = event.get("user", {}).get("id")
 
     # Open a DM with the new user.
-    response = slack_web_client.im_open(user=user_id)
+    response = slack_web_client.conversations_open(users=user_id)
     channel = response["channel"]["id"]
 
     # Post the onboarding message.

tutorial/PythOnBoardingBot/async_app.py

@@ -52,7 +52,7 @@ async def onboarding_message(**payload):
     user_id = payload["data"]["user"]["id"]
 
     # Open a DM with the new user.
-    response = web_client.im_open(user_id)
+    response = web_client.conversations_open(users=user_id)
     channel = response["channel"]["id"]
 
     # Post the onboarding message.