chore(package): update mocha to version 6.2.1

Author: greenkeeper[bot]

package.json

@@ -61,7 +61,7 @@
     "chai-as-promised": "^7.1.1",
     "eslint-config-appium": "^4.2.0",
     "gulp": "^4.0.0",
-    "mocha": "^6.0.0",
+    "mocha": "^6.2.1",
     "pre-commit": "^1.1.3",
     "sinon": "^7.2.3"
   },