fix(package): update react to version 16.4.2

Closes #30

Author: greenkeeper[bot]

package.json

@@ -7,7 +7,7 @@
   "license": "MIT",
   "private": true,
   "dependencies": {
-    "react": "^15.4.2",
+    "react": "^16.4.2",
     "react-dom": "^15.4.2"
   },
   "devDependencies": {