Bump nix from 0.30.1 to 0.31.1 (#49)

Bumps [nix](https://github.com/nix-rust/nix) from 0.30.1 to 0.31.1.
- [Changelog](https://github.com/nix-rust/nix/blob/master/CHANGELOG.md)
- [Commits](nix-rust/nix@v0.30.1...v0.31.1)

---
updated-dependencies:
- dependency-name: nix
  dependency-version: 0.31.1
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

Cargo.lock

@@ -10,7 +10,7 @@ keywords = ["command", "process", "child", "subprocess", "fd"]
 categories = ["os::unix-apis"]
 
 [dependencies]
-nix = { version = "0.30.1", features = ["fs"] }
+nix = { version = "0.31.1", features = ["fs"] }
 thiserror = "2.0.18"
 tokio = { version = "1.49.0", optional = true, default-features = false, features = [
   "process",