Gitlab: Unable to init using nested repos

[syphernl]

I have created a repos.txt with the following:

org/ops/test
org/ops/other/test

However when running mp init --provider=gitlab -f repos.txt this results in an error:

2021/05/27 11:06:05 unable determine repo from line, expected format '{org}/{repo}': org/ops/test

[nathanleiby]

Looks like this is a Gitlab-only feature: https://docs.gitlab.com/ee/user/group/subgroups/

It's not something we support right now, but open to a PR to support it.