v0.8.1

Changed
- [[#187]](https://github.com/rust-vmm/vhost/pull/187) Clean master slave
  - Replaced master/slave with frontend/backend in the codebase and public API.
  - Replaced master/slave with frontend/backend in the crate features.
- Updated dependency bitflags from 1.0 to 2.4
- [[#116]](https://github.com/rust-vmm/vhost/pull/116) Upgrade to 2021 edition

Fixed
- [[#184]](https://github.com/rust-vmm/vhost/pull/184) Safety fixes
- [[#186]](https://github.com/rust-vmm/vhost/pull/186) vhost: Fix clippy warnings.

vhost: release v0.9.0

Release a new version with the following breaking changes:
- replaced master/slave with frontend/backend in public API
- replaced master/slave with frontend/backend in crate features

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

• crates/vhost-user-backend/Cargo.toml[diff]
• crates/vhost/CHANGELOG.md[diff]
• crates/vhost/Cargo.toml[diff]