can't run laravel 5.7 on php8

hi guys I need help for this case I can't run laravel 5.7 on php8, when I do "php artisan serve" I got error:

thrown in /var/www/html/myProject/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 838
PHP Fatal error:  Uncaught ErrorException: Method ReflectionParameter::getClass() is deprecated in /var/www/html/myProject/vendor/laravel/framework/src/Illuminate/Container/Container.php:838

I have tried to update composer required php version form "^7.1.3" to "php": "^7.1.3|^8.0", and when I run composer update I got another error.

Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - laravel/framework[v5.7.0, ..., 5.7.x-dev] require php ^7.1.3 -> your php version (8.0.3) does not satisfy that requirement.
    - Root composer.json requires laravel/framework 5.7.* -> satisfiable by laravel/framework[v5.7.0, ..., 5.7.x-dev].

I hope any body sharing what is solution for this case

via Chebli Mohamed