Update nix requirement from 0.29 to 0.30

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](https://github.com/nix-rust/nix/compare/v0.29.0...v0.30.0)

---
updated-dependencies:
- dependency-name: nix
  dependency-version: 0.30.0
  dependency-type: direct:production
...

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

Cargo.toml

@@ -69,7 +69,7 @@ jni = { version = "0.21", default-features = false }
 
 [target.'cfg(unix)'.dependencies]
 daemonize = "0.5"
-nix = { version = "0.29", default-features = false, features = [
+nix = { version = "0.30", default-features = false, features = [
     "fs",
     "socket",
     "uio",