updated slack invite link

Author: ZeroX-DG

readme.md

@@ -49,7 +49,7 @@ Issues on Boostnote can be funded by anyone and the money will be distributed to
 
 - [Facebook Group](https://www.facebook.com/groups/boostnote/)
 - [Twitter](https://twitter.com/boostnoteapp)
-- [Slack Group](https://join.slack.com/t/boostnote-group/shared_invite/enQtMzkxOTk4ODkyNzc0LWQxZTQwNjBlMDI4YjkyYjg2MTRiZGJhNzA1YjQ5ODA5M2M0M2NlMjI5YjhiYWQzNzgzYmU0MDMwOTlmZmZmMGE)
+- [Slack Group](https://join.slack.com/t/boostnote-group/shared_invite/zt-cun7pas3-WwkaezxHBB1lCbUHrwQLXw)
 - [Blog](https://medium.com/boostnote)
 - [Reddit](https://www.reddit.com/r/Boostnote/)