Fix link in issue template.

Fix #1630.

Author: aaugustin

.github/ISSUE_TEMPLATE/issue.md

@@ -21,7 +21,7 @@ Did you look for similar issues? Please keep the discussion in one place :-)
 https://github.com/python-websockets/websockets/issues?q=is%3Aissue
 
 Is your issue related to cryptocurrency in any way? Please don't file it.
-https://websockets.readthedocs.io/en/stable/project/contributing.html#cryptocurrency-users
+https://websockets.readthedocs.io/en/stable/project/support.html#cryptocurrency-users
 
 For bugs, providing a reproduction helps a lot. Take an existing example and tweak it!
 https://github.com/python-websockets/websockets/tree/main/example