Add InterfaceCustomUnmarshaler

[ozraru]

Is your feature request related to a problem? Please describe. I want to make an unmarshaler of the interface. The interface includes several structs. And it can be identified with type field. I've tried to make CustomUnmarshaler, but there is no CustomUnmarshaler which have the same function as InterfaceUnmarshaler.

Describe the solution you'd like Add func CustomInterfaceUnmarshaler[T any](unmarshaler func(*T, func(interface{}) error) error) DecodeOption
func RegisterCustomInterfaceUnmarshaler[T any](unmarshaler func(*T, func(interface{}) error) error)

Describe alternatives you've considered I've tried to implement InterfaceUnmarshaler, but the interface cannot have function.

Additional context

Example to use

```go type MyInterface interface { foo() } type MyStruct1 struct { UniqueField1 string } func (m *MyStruct1) foo() {} type MyStruct2 struct { UniqueField2 string } func (m *MyStruct2) foo() {} type MyStruct3 struct { UniqueField3 string } func (m *MyStruct3) foo() {} func init() { yaml.RegisterCustomInterfaceUnmarshaler[MyInterface](func(s *MyInterface, unmarshal func(interface{}) error) error { var typeSchema struct { Type string `json:"type"` } if err := unmarshal(&typeSchema); err != nil { return err } switch typeSchema.Type { case "str1": str1 := MyStruct1{} if err := unmarshal(&str1); err != nil { return err } *s = &str1 return nil case "str2": str2 := MyStruct1{} if err := unmarshal(&str2); err != nil { return err } *s = &str2 return nil case "str3": str3 := MyStruct1{} if err := unmarshal(&str3); err != nil { return err } *s = &str3 return nil default: return ErrInvalidType } }) } ```