chore(package): update react to version 15.4.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -49,7 +49,7 @@
     "istanbul": "^0.4",
     "mocha": "^3.0",
     "mocha-lcov-reporter": "^1.2.0",
-    "react": "^15.0",
+    "react": "^15.4.0",
     "react-dom": "^15.0"
   }
 }