Update mocha requirement from ^5.1.1 to ^6.1.4
Update mocha requirement from ^5.1.1 to ^6.1.4

Updates the requirements on [mocha](https://github.com/mochajs/mocha) to permit the latest version.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](https://github.com/mochajs/mocha/compare/v5.1.1...v6.1.4)
abtris/sinopia-htaccess-gpg-email