build(deps): update nix requirement from ^0.29 to ^0.30

Updates the requirements on [nix](https://github.com/nix-rust/nix) to permit the latest version.
- [Changelog](https://github.com/nix-rust/nix/blob/master/CHANGELOG.md)
- [Commits](nix-rust/nix@v0.29.0...v0.30.0)

---
updated-dependencies:
- dependency-name: nix
  dependency-version: 0.30.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.toml

@@ -20,7 +20,7 @@ rust-version = "1.69"
 hmac = "^0.12"
 libc = "^0.2"
 log = "^0.4"
-nix = { version = "^0.29", default-features = false, features = ["dir", "fs", "socket", "process", "uio"] }
+nix = { version = "^0.30", default-features = false, features = ["dir", "fs", "socket", "process", "uio"] }
 nom = "8"
 serde = { version = "^1.0.91", features = ["derive"] }
 sha2 = "^0.10"