updated tokio-util to 0.7 (#969)

Author: conblem

Cargo.toml

@@ -34,7 +34,7 @@ serde_json = "1.0"
 serde_urlencoded = "0.7"
 tokio = { version = "1.0", features = ["fs", "sync", "time"] }
 tokio-stream = "0.1.1"
-tokio-util = { version = "0.6", features = ["io"] }
+tokio-util = { version = "0.7", features = ["io"] }
 tracing = { version = "0.1.21", default-features = false, features = ["log", "std"] }
 tower-service = "0.3"
 tokio-tungstenite = { version = "0.15", optional = true }