Bump crossbeam from 0.8.0 to 0.8.1

Bumps [crossbeam](https://github.com/crossbeam-rs/crossbeam) from 0.8.0 to 0.8.1.
- [Release notes](https://github.com/crossbeam-rs/crossbeam/releases)
- [Changelog](https://github.com/crossbeam-rs/crossbeam/blob/master/CHANGELOG.md)
- [Commits](crossbeam-rs/crossbeam@crossbeam-0.8.0...crossbeam-0.8.1)

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

Author: dependabot[bot]