devel/gitlab-runner: update to 18.6.0

Fixes error in pipeline:
fatal: unable to get password from user

More info:
https://gitlab.com/gitlab-org/gitlab/-/issues/581563
https://gitlab.com/gitlab-org/gitlab-runner/-/issues/39123
https://gitlab.com/gitlab-org/gitlab-runner/-/merge_requests/5958

Changes: https://gitlab.com/gitlab-org/gitlab-runner/blob/v18.6.0/CHANGELOG.md
(cherry picked from commit e79904f596481ac401dad3f65689ddcdc70fc242)