www/gitlab: security and patch update to 18.8.2

Changes: https://about.gitlab.com/releases/2026/01/21/patch-release-gitlab-18-8-2-released/
Security: 61dc7f67-f6e5-11f0-b051-2cf05da270f3
(cherry picked from commit ddde0f2986a0984b4d32abf9094a5a2e3054860e)