尝试将Laravel从版本6升级到版本7时出现问题

Question

您好，Wonderfull所有人，

我们在尝试将Laravel从版本6升级到7时遇到问题。这是错误消息：

Script php artisan optimize handling the post-update-cmd event returned with error code 255

composer.json如下：

{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": [
    "framework",
    "laravel"
],
"license": "MIT",
"type": "project",
"require": {
    "php": "^7.1",
    "laravel/framework": "7.*",
    "venturecraft/revisionable": "1.*",
    "barryvdh/laravel-dompdf": "^0.8.3",
    "doctrine/dbal": "^2.5",
    "guzzlehttp/guzzle": "^6.2",
    "maatwebsite/excel": "^3.1",
    "laravel/passport": "^7.0.0",
    "nesbot/carbon": "^2.39",
    "kylekatarnls/laravel-carbon-2": "^1.0.0"
},
"require-dev": {
    "fzaninotto/faker": "~1.4",
    "mockery/mockery": "0.9.*",
    "phpunit/phpunit": "~5.0",
    "symfony/css-selector": "3.1.*",
    "symfony/dom-crawler": "3.1.*",
    "barryvdh/laravel-ide-helper": "^2.7"
},
"autoload": {
    "classmap": [
        "database"
    ],
    "psr-4": {
        "App\\": "app/"
    }
},
"autoload-dev": {
    "classmap": [
        "tests/TestCase.php"
    ]
},
"scripts": {
    "post-root-package-install": [
        "php -r \"file_exists('.env') || copy('.env.example', '.env');\""
    ],
    "post-create-project-cmd": [
        "php artisan key:generate"
    ],
    "post-install-cmd": [
        "Illuminate\\Foundation\\ComposerScripts::postInstall",
        "php artisan optimize"
    ],
    "post-update-cmd": [
        "Illuminate\\Foundation\\ComposerScripts::postUpdate",
        "php artisan optimize"
    ]
},
"config": {
    "preferred-install": "dist"
}

} 有人知道该怎么做吗？

亲切的问候，

Daan Jansen和Tom van der Hout