chore(package): update mocha to version 7.2.0

Closes #9

Author: greenkeeper[bot]

package.json

@@ -37,6 +37,6 @@
     "semver": "^5.4.1"
   },
   "devDependencies": {
-    "mocha": "^4.0.0"
+    "mocha": "^7.2.0"
   }
 }