moving to libera.chat now

[Timothée Giet]

Hi everyone,

With the current mess on freenode, and as advised by KDE sysadmins, we
are now officially moving away from freenode.

Please everyone join the #gcompris channel on the server irc.libera.chat
for further discussions (see https://libera.chat/ for more info).

The KDE matrix bridge is not ready yet, so you'll need to use an irc
client in the meantime.

Cheers,

Timothée