Update pretty_assertions requirement from ^0.6.1 to ^0.7.1
Update pretty_assertions requirement from ^0.6.1 to ^0.7.1

Updates the requirements on [pretty_assertions](https://github.com/colin-kiegel/rust-pretty-assertions) to permit the latest version.
- [Release notes](https://github.com/colin-kiegel/rust-pretty-assertions/releases)
- [Changelog](https://github.com/colin-kiegel/rust-pretty-assertions/blob/main/CHANGELOG.md)
- [Commits](https://github.com/colin-kiegel/rust-pretty-assertions/compare/v0.6.1...v0.7.1)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>
taskcluster/rust-hawk,taskcluster/rust-hawk