www/gitea: Update to 1.20.0 (fixes security vulnerabilities)
ChangeLog: https://blog.gitea.com/release-of-1.20.0
PR: 272538
Reported by: stb@lassitu.de (maintainer)
MFH: 2023Q3 (security fixes)
(cherry picked from commit 26433938a88c26e618d0512acc3a354dc8eae0a7)