Laravel Update from 4.2 to 5.6

I'm getting the following error when running composer install:

PHP Fatal error: Uncaught ReflectionException: Class App\Console\Kernel does not exist in /home/ubuntu/fusion/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php:788 Stack trace: #0 /home/ubuntu/fusion/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(788): ReflectionClass->__construct('App\Console\Ker...') #1 /home/ubuntu/fusion/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(667): Illuminate\Container\Container->build('App\Console\Ker...') #2 /home/ubuntu/fusion/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(265): Illuminate\Container\Container->resolve('App\Console\Ker...', Array, false) #3 /home/ubuntu/fusion/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(785): Illuminate\Container\Container->Illuminate\Container{closure}(Object(Illuminate\Foundation\Application), Array) #4 /home/ubuntu/fusion/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php(667): Illuminate\Container\Container- in /home/ubuntu/fusion/laravel/vendor/laravel/framework/src/Illuminate/Container/Container.php on line 788

This is what I have in my composer.json

    "require": {
            "php": "^7.1.3",
            "fideloper/proxy": "^4.0",
            "laravel/framework": "5.8.*",
            "laravel/tinker": "^1.0"
        },
        "require-dev": {
            "filp/whoops": "^2.0",
            "fzaninotto/faker": "^1.4",
            "mockery/mockery": "^1.0",
            "nunomaduro/collision": "^2.0",
            "phpunit/phpunit": "^7.0"
        }

Thanks!

via Chebli Mohamed