chore(deps): bump nix from 0.27.1 to 0.28.0

Bumps [nix](https://github.com/nix-rust/nix) from 0.27.1 to 0.28.0.
- [Changelog](https://github.com/nix-rust/nix/blob/master/CHANGELOG.md)
- [Commits](nix-rust/nix@v0.27.1...v0.28.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Cargo.lock

@@ -181,7 +181,7 @@ shadowsocks = { version = "1.18.1", path = "../shadowsocks", default-features =
 
 # Just for the ioctl call macro
 [target.'cfg(any(target_os = "macos", target_os = "ios", target_os = "freebsd"))'.dependencies]
-nix = { version = "0.27", features = ["ioctl"] }
+nix = { version = "0.28", features = ["ioctl"] }
 
 [target.'cfg(windows)'.dependencies]
 windows-sys = { version = "0.52", features = ["Win32_Networking_WinSock"] }