irc/unreal: Deprecate and set expiration date to 2022-06-30

Very outdated, declared end of life by upstream in 2016 and has known
security vulnerabilities

Reference: https://www.unrealircd.org/docs/UnrealIRCd_3.2.x_deprecated

PR:		244117
Reported by:	Rafael Grether <devnull@apt322.org>