readme: move the support channel on libera
This lingered a bit but the Freenode situation is becoming clownier and clownier by the hour.
--HG-- branch : stable
This instance will be upgraded to Heptapod 1.3.1 (GitLab 16.9.3) on 2023-03-28 at 17:00 UTC+1
This lingered a bit but the Freenode situation is becoming clownier and clownier by the hour.
--HG-- branch : stable