⬆️ Bump mocha from 4.0.1 to 6.1.4

Bumps [mocha](https://github.com/mochajs/mocha) from 4.0.1 to 6.1.4.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](mochajs/mocha@v4.0.1...v6.1.4)

Signed-off-by: dependabot-preview[bot] <[email protected]>

Author: dependabot-preview[bot]