chore(package): update mocha to version 6.0.0

Author: greenkeeper[bot]

package.json

@@ -32,7 +32,7 @@
     "@types/node": "^10.11.3",
     "chai": "^4.2.0",
     "husky": "^1.1.0",
-    "mocha": "^3.5.3",
+    "mocha": "^6.0.0",
     "nyc": "^13.0.1",
     "source-map-support": "^0.5.9",
     "ts-node": "^7.0.1",