chore(package): update mocha to version 6.0.0

Author: greenkeeper[bot]

package.json

@@ -31,7 +31,7 @@
  "gulp-istanbul": "1.1.3",
  "gulp-mocha": "6.0.0",
  "istanbul": "0.4.5",
- "mocha": "5.2.0",
+ "mocha": "6.0.0",
  "parse-comments": "0.4.3",
  "shelljs": "0.8.2",
  "shelljs-nodecli": "0.1.1"