Update readme to replace IRC with Discord

Author: cjavilla-stripe

README.md

@@ -77,7 +77,7 @@ independent of the framework.
 If you found a bug or want to suggest a new [feature/use case/sample], please [file an issue](../../issues).
 
 If you have questions, comments, or need help with code, we're here to help:
-- on [IRC via freenode](https://webchat.freenode.net/?channel=#stripe)
+- on [Discord](https://stripe.com/go/developer-chat)
 - on Twitter at [@StripeDev](https://twitter.com/StripeDev)
 - on Stack Overflow at the [stripe-payments](https://stackoverflow.com/tags/stripe-payments/info) tag
 - by [email](mailto:[email protected])