chore(package): update mocha to version 7.1.2

Closes #20

package.json

@@ -37,7 +37,7 @@
   "devDependencies": {
     "express": "~4.16.3",
     "fs-extra": "~6.0.1",
-    "mocha": "~5.2.0",
+    "mocha": "~7.1.2",
     "sinon": "~6.0.0"
   }
 }