www/gitlab-ce: security update to 15.10.6

Changelog:
https://about.gitlab.com/releases/2023/05/05/critical-security-release-gitlab-15-11-2-released/

Security: 89fdbd85-ebd2-11ed-9c88-001b217b3468
(cherry picked from commit c9b398d5a82c306121229a3fb9a3e84e5ea09f8b)