Update Rust crate tokio-tungstenite to 0.28

Author: oxide-renovate[bot]

Cargo.toml

@@ -33,7 +33,7 @@ toml = "0.9"
 propolis-client = { git = "https://github.com/oxidecomputer/propolis", rev = "36f20be9bb4c3b362029237f5feb6377c982395f" }
 libc = "0.2"
 tokio = { version = "1.50.0", features = ["full"] }
-tokio-tungstenite = "0.21"
+tokio-tungstenite = "0.28"
 futures = "0.3"
 clap = { version = "4.5.60", features = ["color", "derive"] }
 tabwriter = { version = "1", features = ["ansi_formatting"] }