Update nix requirement from 0.29.0 to 0.30.0

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@v0.29.0...v0.29.0)

---
updated-dependencies:
- dependency-name: nix
  dependency-version: 0.29.0
  dependency-type: direct:production
...

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

Author: dependabot[bot]

Cargo.toml

@@ -102,7 +102,7 @@ libipt = "0.3.0"
 log = "0.4.22"
 meminterval = "0.4.1"
 mimalloc = { version = "0.1.43", default-features = false }
-nix = { version = "0.29.0", default-features = false }
+nix = { version = "0.30.0", default-features = false }
 num-derive = { version = "0.4.2", default-features = false }
 num_enum = { version = "0.7.3", default-features = false }
 num-traits = { version = "0.2.19", default-features = false }