Unable to install "laravel/ui" into a Laravel 8 project using composer

What I tried:

• composer require laravel/ui
• composer require laravel/ui:^3.2
• Directly update composer.json and composer update

All of the tries above ended up the error below.

  [InvalidArgumentException]
  Could not find package laravel/ui.

  Did you mean this?
      laravel/ui

Versions:

root@e89196703687:/work/backend# php artisan -V
Laravel Framework 8.11.0
root@e89196703687:/work/backend# php -v
PHP 7.4.13 (cli) (built: Dec 11 2020 08:31:11) ( NTS )
Copyright (c) The PHP Group
Zend Engine v3.4.0, Copyright (c) Zend Technologies

composer.jsn

{
    "name": "laravel/laravel",
    "type": "project",
    "description": "The Laravel Framework.",
    "keywords": [
        "framework",
        "laravel"
    ],
    "license": "MIT",
    "require": {
        "php": "^7.3",
        "auth0/login": "^6.1",
        "fideloper/proxy": "^4.2",
        "fruitcake/laravel-cors": "^2.0",
        "guzzlehttp/guzzle": "^7.0.1",
        "laravel/framework": "^8.0",
        "laravel/tinker": "^2.0"
    },
    "require-dev": {
        "facade/ignition": "^2.3.6",
        "friendsofphp/php-cs-fixer": "^2.16",
        "fzaninotto/faker": "^1.9.1",
        "mockery/mockery": "^1.3.1",
        "nunomaduro/collision": "^5.0",
        "phpunit/phpunit": "^9.3"
    },
    "config": {
        "optimize-autoloader": true,
        "preferred-install": "dist",
        "sort-packages": true
    },
    "extra": {
        "laravel": {
            "dont-discover": []
        }
    },
    "autoload": {
        "psr-4": {
            "App\\": "app/",
            "Database\\Factories\\": "database/factories/",
            "Database\\Seeders\\": "database/seeders/"
        }
    },
    "autoload-dev": {
        "psr-4": {
            "Tests\\": "tests/"
        }
    },
    "minimum-stability": "dev",
    "prefer-stable": true,
    "scripts": {
        "post-autoload-dump": [
            "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump",
            "@php artisan package:discover --ansi"
        ],
        "post-root-package-install": [
            "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
        ],
        "post-create-project-cmd": [
            "@php artisan key:generate --ansi"
        ],
        "post-install-cmd": [
            "php artisan clear-compiled",
            "chmod -R 775 public/"
         ],
        "fix": [
            "php-cs-fixer fix"
        ]
    }
}

Any idea?