I have no idea how releases are communicated from Nikto, but there is list of breaking changes for version 2.5.0 here: https://github.com/sullo/nikto/wiki/2.5.0-Potentially-Breaking-Changes and the readme on https://github.com/sullo/nikto states to use the nikto-2.5.0 branch. It looks like the readme on the github page was updated 2022-09-05 to add the comment to use the 2.5.0 branch.
As upstream does not set any tag, I'm going to stay on actual $PV format.
done in https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=0925da33135f07b619aa49dc184d632048c2ae06