build(deps): 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
...

Signed-off-by: dependabot[bot] <support@github.com>