Revert "Updated discord invite."

This reverts commit dc3849f451dc826c8b8f560b2e00a370dc67a1d8.

index.html

@@ -54,7 +54,7 @@
 					<h2>Community</h2>
 					<ul>
 						<li><a href="https://stackoverflow.com/questions/tagged/three.js">questions</a></li>
-						<li><a href="https://discord.com/invite/nYqnAYMh">discord</a></li>
+						<li><a href="https://discord.gg/56GBJwAnUS">discord</a></li>
 						<li><a href="https://discourse.threejs.org/">forum</a></li>
 						<li><a href="https://twitter.com/threejs">twitter</a></li>
 					</ul>