Announce on libera chat when there has been a failure in CI. This uses netcat to connect to the IRC server and send some raw commands when we detect that a build failure has happened. We include the output of `git log --oneline -n 1` in the message. The announcement will only be sent when the `IRC_CHANNEL` env var is set; currently that is set in `.build.yml` and nowhere else. Also remove cloc from the CI runs; it doesn't really add anything for every run and it has more dependencies than I would like.