v4.0.0

• #91: Updated all built-in validation rules to use validation.Error as the validation error type. It supports error code and parameter placeholders in error messages, which allows checking validation errors programmatically and translating error messages based on error codes. Thanks to @mehran-prs for the great contribution to this new feature!
• Improved the performance of Errors.Error(). Thanks to @geekflyer for the profiling work and code contribution!