Update nix requirement from 0.28 to 0.29

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...v0.29.0)

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

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

Cargo.toml

@@ -42,7 +42,7 @@ regex = { version = "1.5.5", optional = true }
 rustyline-derive = { version = "0.10.0", optional = true, path = "rustyline-derive" }
 
 [target.'cfg(unix)'.dependencies]
-nix = { version = "0.28", default-features = false, features = ["fs", "ioctl", "poll", "signal", "term"] }
+nix = { version = "0.29", default-features = false, features = ["fs", "ioctl", "poll", "signal", "term"] }
 utf8parse = "0.2"
 skim = { version = "0.10", optional = true, default-features = false }
 signal-hook = { version = "0.3", optional = true, default-features = false }