General improvements
- Added Ruby 2.6 support
New features
- Added support for deleting project milestones #438
- Added support for deleting merged branches #439
- Added support for listing protected branches #440
- Added support for broadcast messages API #441
- Added support for wikis API #442
- Added support for templates API #444
- Added support for repository submodules API #449
- Added support for protected tags API #451
- Added support for project badges API #452