Recursively search parent directories for .gitlab-ci.yml if not found in current project.

[LauJosefsen]

Is your feature request related to a problem? Please describe. When developing in a local project, I often times find myself in a subdirectory of a git repository, where I want to run gitlab-ci-local, but it cannot find the CI yaml, due to it only existing in the root directory of the git repository.

Describe the solution you'd like When running gitlab-ci-local, it should try and explore parent directories recursively to find a gitlab-ci.yml. This should not happen if a specific gitlab-ci file is specified using the --file parameter.