my project is 5.4.The following error is reported when upgrading to 5.5 using composer update

this is my composer.json partial configuration

.
.
.
"require": {
        "php": ">=5.6.4",
        "barryvdh/laravel-debugbar": "~2.4",
        "doctrine/dbal": "~2.4",
        "laravel/framework": "5.5.*",
        "laravel/tinker": "~1.0",
        "predis/predis": "^1.1"
    },
    .
    .
    . 
"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"
    ],
    "post-autoload-dump":[
        "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump",
        "@php artisan package:discover"
    ]
},

get down on your knees and beg you for an answer. Thank you!