chore: upgrade nix version (#1034)

Author: tisonkun

poem/Cargo.toml

@@ -173,7 +173,7 @@ uuid = { version = "1.8.0", optional = true, default-features = false, features
 ] }
 
 [target.'cfg(unix)'.dependencies]
-nix = { version = "0.29.0", features = ["fs", "user"] }
+nix = { version = "0.30.1", features = ["fs", "user"] }
 
 [dev-dependencies]
 async-stream = "0.3.2"