chore: remove unused dependencies discovered by cargo-machete

stub/Cargo.toml

@@ -8,7 +8,6 @@ edition = "2024"
 clap = { version = "4.6.6", features = ["derive"] }
 reqwest = { version = "0.13", default-features = false, features = ["stream"] }
 tokio = { version = "1.53.1", features = ["full"] }
-tokio-util = { version = "0.7.19", features = ["io"] }
 futures-util = "0.3.34"
 tokio-tungstenite = { version = "0.30.0" }
 tracing-appender = "0.2.5"