Bump nix from 0.26.4 to 0.29.0

Bumps [nix](https://github.com/nix-rust/nix) from 0.26.4 to 0.29.0.
- [Changelog](https://github.com/nix-rust/nix/blob/master/CHANGELOG.md)
- [Commits](nix-rust/nix@v0.26.4...v0.29.0)

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

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

Cargo.toml

@@ -98,7 +98,7 @@ tempfile = "3.8.1"
 serde = { version = "1.0", features = ["derive"] }
 
 [target.'cfg(unix)'.dev-dependencies]
-nix = { version = "0.26.4", default-features = false, features = ["term"] }
+nix = { version = "0.29.0", default-features = false, features = ["term"] }
 
 [build-dependencies]
 anyhow = "1.0.86"