chore(package): update enzyme to version 3.9.0

Closes #29

Author: greenkeeper[bot]

package.json

@@ -19,7 +19,7 @@
     "babel-preset-es2015": "^6.24.0",
     "babel-preset-react": "^6.23.0",
     "codecov": "^2.1.0",
-    "enzyme": "^2.7.1",
+    "enzyme": "^3.9.0",
     "jest": "^19.0.2",
     "lerna": "2.0.0-rc.1",
     "react-addons-test-utils": "^15.4.2",