build(deps): bump proptest from 1.5.0 to 1.6.0

Bumps [proptest](https://github.com/proptest-rs/proptest) from 1.5.0 to 1.6.0.
- [Release notes](https://github.com/proptest-rs/proptest/releases)
- [Changelog](https://github.com/proptest-rs/proptest/blob/main/CHANGELOG.md)
- [Commits](https://github.com/proptest-rs/proptest/commits)

---
updated-dependencies:
- dependency-name: proptest
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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