fix: slack invite link

Author: codediodeio

README.md

@@ -8,7 +8,7 @@ FireStarter is designed to handle the basic features required by most Angular Fi
 
 - [Live Demo](https://firestarter-96e46.firebaseapp.com/)
 - [Lessons and Screencasts](https://angularfirebase.com)
-- [Join the Slack Team](https://join.slack.com/angularfirebase/shared_invite/MjA2NTgxMTI0MTk2LTE0OTg4NTQ4MDAtMjhhZDIzMjc0Mg)
+- [Join the Slack Team](https://join.slack.com/t/angularfirebase/shared_invite/enQtMjU2OTU5OTMyODM3LWU4YTZiMGFhZjJhYmEwYzI1MWFmYTgyMWRmOTI5NWZjYWE3NTMwZjFmNWMwZGI1MmMzODQ3OTFlZjFkMjc5N2Y)
 
 ## Features