Boolean syntax is not fully supported

[Pistonight]

From https://yaml.org/type/bool.html True should be treated as a boolean

let source = "key1: true\nkey2: True";
let obj = serde_yaml::from_str::<serde_json::Value>(source).unwrap();
assert_eq!(obj["key1"].as_bool(), Some(true)); // pass
assert_eq!(obj["key2"].as_str(), Some("True")); // pass - should fail
assert_eq!(obj["key2"].as_bool(), Some(true)); // fail - should pass

serde_yaml version 0.9.12