www/gitea: Update from 1.2.2 to 1.2.3

Changelog: https://blog.gitea.io/2017/11/release-of-1.2.3/

*While here switch to DISTVERSION

PR: 223421
Submitted by: stb@lassitu.de (maintainer)
Approved by: tcberner (mentor)
Differential Revision: https://reviews.freebsd.org/D12953