forking project with custom .gitlab-ci.yml config path should preserve that setting

Problem to solve

Forking project with custom .gitlab-ci.yml config path should preserve that setting

Further details

When forking a project with a custom .gitlab-ci.yml config path (Settings -> CI/CD -> General Pipeline Settings -> Custom CI config path), this setting is not preserved in the fork (as of 10.8.3 c451924358e). This means the CI system will not work the same in the fork.

Proposal

Preserve the custom .gitlab-ci.yml setting in the fork so that the CI system will work the same in the fork as it does in the parent project.