Freenode is gone (replaced by Libera.chat), but IRC was unused anyways.

Fixes: https://github.com/libuv/libuv/issues/3157
Fixes: https://github.com/libuv/libuv/issues/3208
PR-URL: https://github.com/libuv/libuv/pull/3214


Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>