Speed up pipelines with default git shallow clone for all new projects
Problem to Solve
We have a feature for supporting Git Shallow Clone for pipeline jobs. By specifying
git depth, jobs can clone/fetch the code significantly faster than not specifying the value. We don't however provide a reasonable default, so many of our users are not taking advantage of this feature.
As of 12.0, we should set the default project-level
git depth for "new projects only". This will reduce the pipeline duration significantly on the whole GitLab instances.
For the cases, users do not want to do shallow cloning, we should let them nullify
git depth for falling back to the previous behavior by setting it to
0 in the project settings.
Existing projects will not have a default project-level
git depth of 50.