Bump execa from 5.1.1 to 6.0.0

Bumps [execa](https://github.com/sindresorhus/execa) from 5.1.1 to 6.0.0.
- [Release notes](https://github.com/sindresorhus/execa/releases)
- [Commits](sindresorhus/execa@v5.1.1...v6.0.0)

---
updated-dependencies:
- dependency-name: execa
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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