Bump debug from 2.2.0 to 2.6.9

Bumps [debug](https://github.com/visionmedia/debug) from 2.2.0 to 2.6.9.
- [Release notes](https://github.com/visionmedia/debug/releases)
- [Changelog](https://github.com/visionmedia/debug/blob/2.6.9/CHANGELOG.md)
- [Commits](debug-js/debug@2.2.0...2.6.9)

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Author: dependabot[bot]