fix(package): update react-dom to version 16.4.1

Closes #384

Author: greenkeeper[bot]

package.json

@@ -74,7 +74,7 @@
     "react": "16.4.1",
     "react-addons-css-transition-group": "15.6.0",
     "react-addons-test-utils": "15.6.0",
-    "react-dom": "15.6.1",
+    "react-dom": "16.4.1",
     "request": "2.81.0",
     "rimraf": "2.6.1",
     "sinon": "2.3.5",