build: drop unused dependency on futures-util

Author: paolobarbolini

Cargo.toml

@@ -35,7 +35,6 @@ tokio = "1.0"
 tokio-rustls = { version = "0.26", default-features = false }
 tower-service = "0.3"
 webpki-roots = { version = "0.26", optional = true }
-futures-util = { version = "0.3", default-features = false }
 
 [dev-dependencies]
 cfg-if = "1"