chore(package): update mocha to version 6.0.2

Closes #216

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
     "eslint-plugin-jsx-a11y": "^5.1.1",
     "eslint-plugin-react": "^7.3.0",
     "istanbul": "0.4.5",
-    "mocha": "^5.2.0"
+    "mocha": "^6.0.2"
   },
   "peerDependencies": {
     "eslint": "^3.17.0 || ^4 || ^5"