Summary: Bug fix. Currenty Flipper provides incorrect red and green diff colors in Dark theme, this PR fixes the issue. Light theme colors are the same. Closes https://github.com/facebook/flipper/issues/3011 ## Changelog Color theme fix: make diff background colors be defined in theme LESS files Pull Request resolved: https://github.com/facebook/flipper/pull/3065 Test Plan: I used [redux-debugger](https://github.com/jk-gan/flipper-plugin-redux-debugger) plugin to test this as this is what I actually use for debugging Redux in React Native projects with Flipper. Here's a [React Native app](https://github.com/3rdp/flipper-redux-debugger-app) that I put together for testing purposes. Light theme:  Dark theme:  Reviewed By: mweststrate Differential Revision: D32529276 Pulled By: passy fbshipit-source-id: 3d11edaf1112444bb106521b6b30db4a4c2b8202
flipper-plugin
flipper-plugin is the dependency used by all modern Flipper plugins (project "Tommy").
For background: https://fb.quip.com/YHOGAnaPqAVJ
flipper-plugin is to be used as dev and peer dependency of all Flipper plugins. It provides:
- (TODO) Standard API's to interact with Flipper, such as the client connection.
- (TODO) Standard components to organize the UI
- (TODO) Testing utilities
API's provided by flipper-plugin are documented at fbflipper.com (TODO).
There should normally be no need to install flipper-plugin as dependency.
Rather, plugins should be scaffolded using npx flipper-pkg init (TODO) as documented here