build(deps-dev): bump mocha from 5.2.0 to 6.0.0

Bumps [mocha](https://github.com/mochajs/mocha) from 5.2.0 to 6.0.0.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](mochajs/mocha@v5.2.0...v6.0.0)

Signed-off-by: dependabot[bot] <support@dependabot.com>

package.json

@@ -42,7 +42,7 @@
     "eslint-plugin-eslint-plugin": "^2.0.0",
     "eslint-plugin-node": "^8.0.0",
     "eslint-plugin-self": "^1.1.0",
-    "mocha": "^5.2.0",
+    "mocha": "^6.0.0",
     "prettier": "^1.15.3",
     "vue-eslint-parser": "^6.0.0"
   },