Bumps [mocha](https://github.com/mochajs/mocha) from 2.5.3 to 5.2.0.
- [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/v2.5.3...v5.2.0)
Signed-off-by: dependabot[bot] <support@dependabot.com>