Bump flat from 4.1.0 to 5.0.2

Bumps [flat](https://github.com/hughsk/flat) from 4.1.0 to 5.0.2.
- [Release notes](https://github.com/hughsk/flat/releases)
- [Commits](hughsk/flat@4.1.0...5.0.2)

---
updated-dependencies:
- dependency-name: flat
  dependency-type: indirect
...

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