message: docs: format greenkeeper badge
diff: # Terminus UI Library
  -[![Greenkeeper badge](https://badges.greenkeeper.io/GetTerminus/terminus-ui.svg)](https://greenkeeper.io/)
  +[![Greenkeeper badge][greenkeeper_badge]][greenkeeper]
  The library of UI components used for Terminus applications.
  @@ -11,6 +11,7 @@ The library of UI components used for Terminus applications.
  ## Resources
  - [Semantic Release][semantic_release]
  +- [Greenkeeper][greenkeeper]
  [compodoc_badge]: https://rawgit.com/GetTerminus/terminus-ui/master/docs/images/coverage-badge.svg
  @@ -21,5 +22,7 @@ The library of UI components used for Terminus applications.
  [npm_version_image]: http://img.shields.io/npm/v/@terminus/ui.svg
  [circle_badge]: https://circleci.com/gh/GetTerminus/terminus-ui/tree/master.svg?style=svg
  [circle_link]: https://circleci.com/gh/GetTerminus/terminus-ui/tree/master
  +[greenkeeper_badge]: https://badges.greenkeeper.io/GetTerminus/terminus-ui.svg
  +[greenkeeper]: https://greenkeeper.io/
  [semantic_release]: https://github.com/semantic-release/semantic-release
  