I've recently made an iOS App that integrates with GitLab. The people at GitLab have been incredible, they respond to my issues, improve the API with every release, I didn't expect this level of awesomeness when I started the project.

What's great about GitLab, there's a release on the 22nd of each month, so you can depend on pretty much continual improvement. Even if you don't think GitLab is suitable for your Open Source project, talk to the team on their issue tracker, things get solved pretty quickly!