chore(package): update gulp-mocha to version 7.0.0 (#165)

Author: greenkeeper[bot]

package.json

@@ -54,7 +54,7 @@
     "gulp-exec": "^4.0.0",
     "gulp-header": "^2.0.5",
     "gulp-less": "^4.0.1",
-    "gulp-mocha": "^6.0.0",
+    "gulp-mocha": "^7.0.0",
     "gulp-sass": "^4.0.1",
     "gulp-scss-lint": "^1.0.0",
     "jsdom": "^15.0.0",