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
All legacy (hg-git based) Projects have been automatically migrated to native with the upgrade of 2025-01-23
This lingered a bit but the Freenode situation is becoming clownier and clownier by the hour.
--HG-- branch : stable