chore(package): update mocha to version 4.0.0

Author: greenkeeper[bot]

package.json

@@ -46,7 +46,7 @@
     "enzyme": "^2.8.2",
     "jest": "^20.0.0",
     "lodash": "^4.0.0",
-    "mocha": "^3.5.3",
+    "mocha": "^4.0.0",
     "most": "^1.2.2",
     "most-subject": "^5.3.0",
     "nightmare": "^2.10.0",