chore(deps): bump nix from 0.26.4 to 0.28.0

Bumps [nix](https://github.com/nix-rust/nix) from 0.26.4 to 0.28.0.
- [Changelog](https://github.com/nix-rust/nix/blob/master/CHANGELOG.md)
- [Commits](nix-rust/nix@v0.26.4...v0.28.0)

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

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Cargo.lock

@@ -11,5 +11,5 @@ homepage.workspace = true
 anyhow = "1.0"
 conformance-tests = { git = "https://github.com/fermyon/conformance-tests", ref = "db0ee32a825561d35f884a246e1d390134d78823"  }
 log = "0.4"
-nix = "0.26"
+nix = "0.28"
 test-environment = { git = "https://github.com/fermyon/conformance-tests", ref = "db0ee32a825561d35f884a246e1d390134d78823" }