Bump deep-extend and rc

Bumps [deep-extend](https://github.com/unclechu/node-deep-extend) and [rc](https://github.com/dominictarr/rc). These dependencies needed to be updated together.

Updates `deep-extend` from 0.4.2 to 0.6.0
- [Changelog](https://github.com/unclechu/node-deep-extend/blob/master/CHANGELOG.md)
- [Commits](unclechu/node-deep-extend@v0.4.2...v0.6.0)

Updates `rc` from 1.2.5 to 1.2.8
- [Commits](https://github.com/dominictarr/rc/commits)

---
updated-dependencies:
- dependency-name: deep-extend
  dependency-type: indirect
- dependency-name: rc
  dependency-type: indirect
...

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Author: dependabot[bot]