Update nix requirement from 0.27.1 to 0.28.0 in /object_store

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@v0.27.1...v0.28.0)

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

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

object_store/Cargo.toml

@@ -56,7 +56,7 @@ rustls-pemfile = { version = "2.0", default-features = false, features = ["std"]
 tokio = { version = "1.25.0", features = ["sync", "macros", "rt", "time", "io-util"] }
 
 [target.'cfg(target_family="unix")'.dev-dependencies]
-nix = { version = "0.27.1", features = ["fs"] }
+nix = { version = "0.28.0", features = ["fs"] }
 
 [features]
 cloud = ["serde", "serde_json", "quick-xml", "hyper", "reqwest", "reqwest/json", "reqwest/stream", "chrono/serde", "base64", "rand", "ring"]