Added support for an array containing a backed enum type

[refring]

Hi, this change allows lists of backed enums without having to implement fromJsonData() on the enum.

Given the following enum:

enum Status : string
{
    case ON = 'ON';
    case OFF = 'OFF';
}

And the following property:

 #[Json('status_list', type: Status::class)]
 public array $statusList;

A json document like the following would return 3 Status enums:

{"status_list": ["ON", "OFF", "ON"]}

[CLAassistant]

All committers have signed the CLA.

[khepin]

Thank you, this looks pretty good. Would like to update one or 2 things before this makes it in.

[refring]

Thanks for the feedback, I've made the changes you suggested.