Update nix requirement from 0.30.1 to 0.31.1 in /crates/lib

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@v0.30.1...v0.31.1)

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

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

Author: dependabot[bot]

crates/lib/Cargo.toml

@@ -28,7 +28,7 @@ tokio-tar = "0.3.1"
 tokio-util = { version = "0.7.13", features = ["compat"] }
 futures = "0.3.31"
 lazy_static = "1.5.0"
-nix = { version = "0.30.1", features = ["process"] }
+nix = { version = "0.31.1", features = ["process"] }
 fs2 = "0.4.3"
 tempfile = "3.16.0"