www/gitea: update to 1.19.1

ChangeLog: https://blog.gitea.io/2023/04/gitea-1.19.1-is-released/

Add UPDATING entry for breaking change.

PR: 270819
Reported by: stb@lassitu.de (maintainer)
MFH: 2023Q2 (many bugfixes)

(cherry picked from commit 02c406b096d980e385fcb4f55fdc03d4d61f8782)