Add compatibility with Laravel 12

[z4nder]

Description

Laravel 12 has been officially released, and I noticed that the current composer.json constraint for illuminate/support is:

"illuminate/support": "^9.0|^10.0|^11.0"

Because of that, it's currently not possible to install deepseek-laravel in Laravel 12 projects without a version conflict.

I’d like to open a pull request to add support for Laravel 12 by updating the version constraint to:

"illuminate/support": "^9.0|^10.0|^11.0|^12.0"