chore(package): update mocha to version 6.1.4

Closes #70

Author: greenkeeper[bot]

package.json

@@ -43,7 +43,7 @@
     "gulp-connect": "^5.6.1",
     "gulp-jshint": "^1.11.2",
     "gulp-uglify": "^3.0.1",
-    "mocha": "^2.3.3",
+    "mocha": "^6.1.4",
     "mocha-lcov-reporter": "^1.2.0",
     "vinyl-buffer": "^1.0.0",
     "vinyl-source-stream": "^1.1.0"