Fix expired Discord link

Author: mcauser

README.rst

@@ -6,7 +6,7 @@ Adafruit IO Python
     :alt: Documentation Status
 
 .. image:: https://img.shields.io/discord/327254708534116352.svg
-   :target: https://discord.gg/nBQh6qu
+   :target: https://adafru.it/discord
    :alt: Chat
 
 .. image:: https://github.com/adafruit/Adafruit_IO_Python/workflows/Build%20CI/badge.svg