Add support for when;

[zero-to-prod]

Description

Use when to call a function based on a condition.

class User
{
    use \Zerotoprod\DataModel\DataModel;
    use \Zerotoprod\DataModelHelper\DataModelHelper;

    #[Describe([
        'cast' => [self::class, 'when'],
        'eval' => '$value >= $context["value_2"]' // The expression to evaluate.
        'true' => [MyAction::class, 'passed'],    // Optional. Invoked when condition is true.
        'false' => [MyAction::class, 'failed'],   // Optional. Invoked when condition is true.
        'required',                               // Throws PropertyRequiredException when value not present.
    ])]
    public string $value;
}