fix(cargo-credential): should enable feature serde/derive

Author: weihanglo

credential/cargo-credential/Cargo.toml

@@ -7,6 +7,6 @@ repository = "https://github.com/rust-lang/cargo"
 description = "A library to assist writing Cargo credential helpers."
 
 [dependencies]
-serde.workspace = true
+serde = { workspace = true, features = ["derive"] }
 serde_json.workspace = true
 time.workspace = true