Drop the union feature from smallvec for 1.45

crates/proto/Cargo.toml

@@ -75,7 +75,7 @@ openssl = { version = "0.10", features = ["v102", "v110"], optional = true }
 rand = "0.8"
 ring = { version = "0.16", optional = true, features = ["std"] }
 serde = { version = "1.0", features = ["derive"], optional = true }
-smallvec = { version = "1.6", features = ["union"] }
+smallvec = "1.6"
 socket2 = { version = "0.3.16", optional = true }
 thiserror = "1.0.20"
 tinyvec = { version = "1.1.1", features = ["alloc"] }