chore(package): update mocha to version 6.2.2

Closes #22

Author: greenkeeper[bot]

package.json

@@ -25,7 +25,7 @@
     "dodo": "0.0.14",
     "express": "^4.14.0",
     "knex": "0.13.0",
-    "mocha": "^3.1.0",
+    "mocha": "^6.2.2",
     "npm-check": "^5.2.3",
     "nsp": "^2.6.1",
     "objection": "^0.8.0",