www/gitlab: security and patch update to 18.2.1

Changes: https://about.gitlab.com/releases/2025/07/23/patch-release-gitlab-18-2-1-released/
Security: 5683b3a7-683d-11f0-966e-2cf05da270f3
(cherry picked from commit 30b34b77af0a3e6af8d0ba302c68605f425f3ae7)