Must be one of the following:
- feat: A new feature
- fix: A bug fix
- docs: Documentation only changes
- style: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
- refactor: A code change that neither fixes a bug nor adds a feature
- perf: A code change that improves performance
- test: Adding missing or correcting existing tests
- chore: Changes to the build process or auxiliary tools and libraries such as documentation generation
https://github.com/angular/angular.js/blob/master/DEVELOPERS.md#type