Bump mocha from 6.2.0 to 6.2.2

Bumps [mocha](https://github.com/mochajs/mocha) from 6.2.0 to 6.2.2.
- [Release notes](https://github.com/mochajs/mocha/releases)
- [Changelog](https://github.com/mochajs/mocha/blob/master/CHANGELOG.md)
- [Commits](mochajs/mocha@v6.2.0...v6.2.2)

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