www/gitea: Update to 1.21.6 (fixes security vulnerabilities)

ChangeLog: https://github.com/go-gitea/gitea/releases/tag/v1.21.6

		https://blog.gitea.com/release-of-1.21.6/

PR: 277275
MFH: 2024Q1
Security: 5ecfb588-d2f4-11ee-ad82-dbdfaa8acfc2
(cherry picked from commit 0806b5e2f75eb6847a849332c96dd40f8f8f0461)