Update nix requirement from 0.28 to 0.30 (#6)

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@v0.28.0...v0.30.1)

---
updated-dependencies:
- dependency-name: nix
  dependency-version: 0.30.1
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

Cargo.toml

@@ -157,7 +157,7 @@ thiserror = "2.0.17"
 
 [dev-dependencies]
 criterion = "0.7.0"
-nix = { version = "0.28", features = ["fs"] }
+nix = { version = "0.30", features = ["fs"] }
 proptest = "1.8.0"
 
 # The profile that 'dist' will build with