Enable greenkeeper

Summary:
Close https://github.com/facebook/flipper/pull/580

This enables Greenkeeper with some caveats:

- I disabled a bunch of upgrades we know currently break:
  - React
  - Emotion
  - Electron/Electron-Builder
- The bot isn't CLA-whitelisted yet, so we won't be able to directly import yet.
- It might actually be better to have automatic tasks created for the dependencies above breaking.
- Something changed in the prop types and required `StatusBar` to have its signature changed.

allow-large-files

Reviewed By: jknoxville

Differential Revision: D17906693

fbshipit-source-id: f73fe231518f56a6f6114f761d5e5e5528d0d487

README.md

@@ -1,4 +1,4 @@
-# Flipper [![Build Status](https://travis-ci.org/facebook/flipper.svg?branch=master)](https://travis-ci.org/facebook/flipper) [![Android Maven Badge](https://img.shields.io/maven-metadata/v/https/jcenter.bintray.com/com/facebook/flipper/flipper/maven-metadata.xml.svg?color=green&label=android)](https://bintray.com/facebook/maven/com.facebook.flipper%3Aflipper) [![iOS](https://img.shields.io/cocoapods/v/FlipperKit.svg?label=iOS&color=blue)](https://cocoapods.org/pods/Flipper)
+# Flipper [![Build Status](https://travis-ci.org/facebook/flipper.svg?branch=master)](https://travis-ci.org/facebook/flipper) [![Android Maven Badge](https://img.shields.io/maven-metadata/v/https/jcenter.bintray.com/com/facebook/flipper/flipper/maven-metadata.xml.svg?color=green&label=android)](https://bintray.com/facebook/maven/com.facebook.flipper%3Aflipper) [![iOS](https://img.shields.io/cocoapods/v/FlipperKit.svg?label=iOS&color=blue)](https://cocoapods.org/pods/Flipper) [![Greenkeeper badge](https://badges.greenkeeper.io/facebook/flipper.svg)](https://greenkeeper.io/)
 
 Flipper (formerly Sonar) is a platform for debugging mobile apps on iOS and Android. Visualize, inspect, and control your apps from a simple desktop interface. Use Flipper as is or extend it using the plugin API.