title: Can't make "composer require laravel/ui --dev" on laravel 6.5.1
body: <p>I am getting following error : </p>
  
  <blockquote>
    <p>Can't make "composer require laravel/ui --dev" on laravel 6.5.1. I get an error 
    "Your requirements could not be resolved to an installable set of packages.</p>
  </blockquote>
  
  <p>Problem 1: </p>
  
  <ul>
  <li>Conclusion: remove laravel/framework v6.5.1</li>
  <li>Conclusion: don't install laravel/framework v6.5.1</li>
  </ul>
  
  <p>Installation failed, reverting ./composer.json to its original content.</p>
  
  <p>In my <code>composer.json</code> </p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>    "name": "laravel/laravel",
      "type": "project",
      "description": "The Laravel Framework.",
      "keywords": [
          "framework",
          "laravel"
      ],
      "license": "MIT",
      "require": {
          "php": "^7.2",
          "fideloper/proxy": "^4.0",
          "laravel/framework": "^6.2",
          "laravel/tinker": "^1.0",
          "laravelcollective/html": "^5.2.0",
          "tcg/voyager": "^1.3"
      },
      "require-dev": {
          "facade/ignition": "^1.4",
          "fzaninotto/faker": "^1.4",
          "mockery/mockery": "^1.0",
          "nunomaduro/collision": "^3.0",
          "phpunit/phpunit": "^8.0"
      },
      "config": {
          "optimize-autoloader": true,
          "preferred-install": "dist",
          "sort-packages": true
      },
      "extra": {
          "laravel": {
              "dont-discover": []
          }
      },
      "autoload": {
          "psr-4": {
              "App\\": "app/"
          },
          "classmap": [
              "database/seeds",
              "database/factories"
          ]
      },
      "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"
          ]
      },
      "repositories": {
          "hooks": {
              "type": "composer",
              "url": "https://larapack.io"
          }
      }
  }</code></pre>
  </div>
  </div>
  </p>
  
  <p>Php version 7.2.25
  Please, help.</p>