ignore phpstorm attributes when instantiating and add readonly property

[jhavenz]

This package throws an error while instantiating a data class if/when a built-in php storm attribute is used on a dto class.
e.g.:

#[\JetBrains\PhpStorm\Immutable]
class PhpStormClassAttributeData extends Data
{
    public function __construct(public string $property)
    {
        $this->property = $property;
    }
}

and/or

class PhpStormClassAttributeData extends Data
{
    #[\JetBrains\PhpStorm\Immutable]
    public string $property;

    public function __construct(string $property)
    {
        $this->property = $property;
    }
}

and/or

class PhpStormClassAttributeData extends Data
{
    public function __construct(
       #[\JetBrains\PhpStorm\Immutable]
       public string $property
    ) {
       //
    }
}

I'm using \JetBrains\PhpStorm\Immutable in these examples, but I've written this PR to ignore any of the other attributes that they have within the same namespace

---

In the process of fixing this functionality, I came across the need to add the a 'isReadonly' property to the DataType class ... I was actually surprised it wasn't already there. Though, despite me using this package (and source-diving) it quite a bit, maybe its elsewhere in the library and I'm just unaware. Just lmk.

Love the package, thx for the great work!

[rubenvanassche]

Thanks for your PR, I've left a few remarks + could you also provide tests for the readonly functionality. And is it possible to add support for PHP 8.2 readonly classes? So we can get it in one go!

Thanks!

[jhavenz]

Ok, no problem. Your comments make good sense to me. Ill get them fixed up.

[jhavenz]

@rubenvanassche
While working on your requested changes, I've realized that checking if a Data class is readonly is somewhat irrelevant since the abstract \Spatie\LaravelData\Data class itself is not readonly - and as of now, 8.2 won't allow readonly classes to extend non-readonly classes.
At some point, you may want to consider splitting the abstract \Spatie\LaravelData\Data class into 2 base classes, so they can then be extended for readonly/non-readonly purposes. But as of now, I currently have the $isReadonly property implemented on both the DataClass and the DataProperty class.

You think I should just keep these properties as they are, though the DataClass::isReadonly property won't really get used? I'm also not able to test the DataClass::isReadonly property for these same reasons.
Or, just keep the $isReadonly property or on the DataProperty since it's the only one being used?

[jhavenz]

Ok, I've pushed up the changes I've made. If you decide you'd like to keep the DataClass::isReadonly property, this PR is good to go with the changes you've requested.

[rubenvanassche]

Thanks!