This makes it possible to stream data coming
from another server straight into the POST request to Gitlab,
saving an extra, expensive, and useless IO operation on disk.

Ensuring test SystemHooks are removed if tests fail, adding commentary/todo to address GitLab issue at future date

- readme_url
- can_create_merge_request_in
- import_status
- ci_default_git_depth
- remove_source_branch_after_merge
- auto_devops_enabled
- auto_devops_deploy_strategy
- auto_devops_enabled
- statistics.packages_size
- shared_with_groups.group_full_path

fix #613 #632 #667

Added option to preserve underscores in the JacksonJsonEnumHelper to fix TargetType.MERGE_REQUEST value. (#615)

Remove UserListSerializer and UserListDeserializer from approvedBy field in ApprovalRule (fixes #589) (#590)