Update vhost requirement from 0.3 to 0.4

Updates the requirements on [vhost](https://github.com/rust-vmm/vhost) to permit the latest version.
- [Release notes](https://github.com/rust-vmm/vhost/releases)
- [Changelog](https://github.com/rust-vmm/vhost/blob/main/CHANGELOG.md)
- [Commits](rust-vmm/vhost@v0.3.0...v0.4.0)

---
updated-dependencies:
- dependency-name: vhost
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.toml

@@ -10,14 +10,14 @@ license = "Apache-2.0"
 [dependencies]
 libc = ">=0.2.39"
 log = ">=0.4.6"
-vhost = { version = "0.3", features = ["vhost-user-slave"] }
+vhost = { version = "0.4", features = ["vhost-user-slave"] }
 virtio-bindings = "0.1"
 virtio-queue = "0.2"
 vm-memory = {version = "0.7", features = ["backend-mmap", "backend-atomic"]}
 vmm-sys-util = "0.9"
 
 [dev-dependencies]
 nix = "0.23"
-vhost = { version = "0.3", features = ["vhost-user-master", "vhost-user-slave"] }
+vhost = { version = "0.4", features = ["vhost-user-master", "vhost-user-slave"] }
 vm-memory = {version = "0.7", features = ["backend-mmap", "backend-atomic", "backend-bitmap"]}
 tempfile = "3.2.0"