Merge pull request zcash#6898 from PierreCrb/patch-1

Update README.md: fix discord link

README.md

@@ -61,7 +61,7 @@ for instructions on joining the main Zcash network.
 * :blue_book: See the documentation at the [ReadTheDocs](https://zcash.readthedocs.io)
   for help and more information.
 * :incoming_envelope: Ask for help on the [Zcash](https://forum.z.cash/) forum.
-* :speech_balloon: Join our community on [Discord](https://discordapp.com/invite/PhJY6Pm)
+* :speech_balloon: Join our community on [Discord](https://discord.com/invite/zcash) 
 * 🧑‍🎓: Learn at [ZecHub](https://wiki.zechub.xyz/)
 
 Participation in the Zcash project is subject to a