Merge pull request #27 from nathanchance/irc-discord

Update IRC channel location and add Discord

Author: nathanchance

readme.md

@@ -26,8 +26,9 @@
 - [Wiki](https://github.com/ClangBuiltLinux/linux/wiki)
 - [Repos](https://github.com/ClangBuiltLinux)
 - Mailing List: `clang-built-linux@googlegroups.com` ([archive](https://groups.google.com/forum/#!forum/clang-built-linux))
-- IRC: `#clangbuiltlinux` on chat.freenode.net ([webchat](http://webchat.freenode.net/?channels=clangbuiltlinux))
+- IRC: `#clangbuiltlinux` on [irc.libera.chat](https://libera.chat/guides/clients)
 - Telegram: [@ClangBuiltLinux](https://t.me/ClangBuiltLinux)
+- Discord: `#clang-built-linux` in the [LLVM server](https://discord.gg/xS7Z362)
 - Bi-weekly video meeting
   - [Calendar](https://calendar.google.com/calendar/embed?src=google.com_bbf8m6m4n8nq5p2bfjpele0n5s%40group.calendar.google.com)
   - [Hangouts Meet](https://meet.google.com/yjf-jyqk-iaz)