Replace Discord links with PS chat

Author: thomashoneyman

.github/ISSUE_TEMPLATE/config.yml

@@ -4,5 +4,5 @@ contact_links:
     url: https://discourse.purescript.org/
     about: Ask and answer questions on the PureScript discussion forum.
   - name: PureScript Discord
-    url: https://discord.com/invite/sMqwYUbvz6/
+    url: https://purescript.org/chat
     about: Ask and answer questions on the PureScript chat.

README.md

@@ -71,7 +71,7 @@ You may also be interested in other libraries in the Argonaut ecosystem:
 If you get stuck, there are several ways to get help:
 
 - [Open an issue](https://github.com/purescript-contrib/purescript-argonaut-traversals/issues) if you have encountered a bug or problem.
-- Ask general questions on the [PureScript Discourse](https://discourse.purescript.org) forum or the [PureScript Discord](https://discord.com/invite/sMqwYUbvz6) chat.
+- Ask general questions on the [PureScript Discourse](https://discourse.purescript.org) forum or the [PureScript Discord](https://purescript.org/chat) chat.
 
 ## Contributing