chore(deps-dev): bump mocha from 6.1.4 to 6.2.0

Bumps [mocha](https://github.com/mochajs/mocha) from 6.1.4 to 6.2.0.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](mochajs/mocha@v6.1.4...v6.2.0)

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

package.json

@@ -63,7 +63,7 @@
     "gavel-spec": "4.0.0",
     "husky": "3.0.0",
     "lint-staged": "9.2.0",
-    "mocha": "6.1.4",
+    "mocha": "6.2.0",
     "nyc": "14.1.1",
     "prettier": "1.18.2",
     "rollup": "1.17.0",