laracasts generators Installation failed

I got the error message. When I composer require laracasts/generators --dev . Is the laracasts/generators doesn't support laravel framework version 5.8? Or others issues caused?

Problem 1
  - Root composer.json requires laracasts/generators ^2.0 -> satisfiable by laracasts/generators[2.0.0].
  - laracasts/generators 2.0.0 requires illuminate/support ~6.0|~7.0|~8.0 -> found illuminate/support[v6.0.0, ..., 6.x-dev, v7.0.0, ..., 7.x-dev, v8.0.0, ..., 8.x-dev] but these were not loaded, likely because it conflicts with another require.


Installation failed, reverting ./composer.json and ./composer.lock to their original content.

Composer json file

"require": {
    "php": "^7.1.3",
    "backpack/base": "^1.1.9",
    "backpack/crud": "3.6.*",
    "encore/laravel-admin": "^1.8",
    "fideloper/proxy": "^4.0",
    "laravel-admin-ext/redis-manager": "^1.3",
    "laravel/framework": "5.8.*",
    "laracasts/generators": "^2.0",
    "laravel/tinker": "^1.0",
    "leantony/laravel-grid": "2.0.x-dev"
},

So I try to run command php artisan backpack:base:install

 Installing backpack/generators
 2/8 [▓▓▓▓▓▓▓░░░░░░░░░░░░░░░░░░░░░]  25% Installing laracasts/generators

   Symfony\Component\Process\Exception\ProcessFailedException  : The command "composer require laracasts/generators:dev-master --dev" failed.

Exit Code: 2(Misuse of shell builtins)

Working directory: /Applications/MAMP/htdocs/myProject

Output:
================


Error Output:
================
./composer.json has been updated
Running composer update laracasts/generators
Loading composer repositories with package information
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Root composer.json requires laracasts/generators dev-master -> satisfiable by laracasts/generators[dev-master].
    - laracasts/generators dev-master requires illuminate/support ~6.0|~7.0|~8.0 -> found illuminate/support[v6.0.0, ..., 6.x-dev, v7.0.0, ..., 7.x-dev, v8.0.0, ..., 8.x-dev] but these were not loaded, likely because it conflicts with another require.

Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.

Installation failed, reverting ./composer.json and ./composer.lock to their original content.

via Chebli Mohamed