Repo copier: 404 failed to parse unknown error format with Gitlab URL

[zackproser]

A customer asked:

I'm encountering an error where the repo-copier fails to parse a destination URL:

The example target is

gitlab https://domain.com/gitlab/project/repo

The failure is

ERROR:  GET https://domain/api/v4/namespaces/gitlab/project/repo: 404 failed to parse unknown error format

[zackproser]

The path should contain the full path to a GitLab group. GitLab group is a kind of GitHub organization. Please make sure you specify the exact group, not a repository or user.

credit for this answer goes to @levkoburburas