Catch exception when an artifact doesn't exist.
The major version of GitLab may come with a change of the exception when an artifact that doesn't exist is requested. Before it raises a 'GitlabGerError' with a 404 code, and now it shows a request exception.
This produced tenacity to retry to get something that is known it doesn't exist. We can maintain the previous error catch and extent with the newer seen.
This solves #2 (closed)