chore(package): update mocha to version 7.1.2

Closes #23

Author: greenkeeper[bot]

package.json

@@ -26,7 +26,7 @@
   "devDependencies": {
     "eslint": "^6.0.0",
     "eslint-config-guo": "^0.9.0",
-    "mocha": "^6.0.0",
+    "mocha": "^7.1.2",
     "request": "^2.82.0",
     "should": "^13.1.0"
   }