Update about.md

Author: anistark

about.md

@@ -15,5 +15,5 @@ The group maintains a <a target="_blank" rel="noopener noreferrer" href="http://
 <a target="_blank" rel="noopener noreferrer" href="http://mail.python.org/mailman/listinfo/bangpypers">Join our mailing list</a> | <a target="_blank" rel="noopener noreferrer" href="http://www.meetup.com/BangPypers/">Visit our meetup page</a> | <a target="_blank" rel="noopener noreferrer" href="http://www.bangpypers.slack.com/">Join us on Slack</a>
 </p>
 <p>
-If you need a Slack invite, <a target="_blank" rel="noopener noreferrer" href="http://bit.ly/join_bangpypers_slack">click here.</a>
-</p>
+If you need a Slack invite, <a target="_blank" rel="noopener noreferrer" href="https://join.slack.com/t/bangpypers/shared_invite/zt-84wr9lom-RKtc~mw9eHdvw~8_YPaKQg">click here.</a>
+</p>