Merge pull request #42 from reactive-react/greenkeeper/jest-21.0.0

Update jest to the latest version 🚀

Author: jcouyang

package.json

@@ -46,7 +46,7 @@
     "create-react-class": "^15.6.0",
     "envify": "^4.1.0",
     "enzyme": "^2.8.2",
-    "jest": "^20.0.0",
+    "jest": "^21.0.0",
     "lodash": "^4.0.0",
     "mocha": "^3.5.3",
     "most": "^1.2.2",