chore(package): update mocha to version 6.2.0

Closes #7

Author: greenkeeper[bot]

package.json

@@ -38,7 +38,7 @@
     "eslint": "^5.12.0",
     "eslint-config-airbnb-base": "^13.1.0",
     "eslint-plugin-import": "^2.14.0",
-    "mocha": "^5.2.0",
+    "mocha": "^6.2.0",
     "nock": "^10.0.6",
     "nyc": "^13.1.0",
     "pre-commit": "^1.2.2",