Change polyfill-php56 to polyfill-php72 [upgrade laravel 5 to 7]

I'm trying to update my laravel project from 5.8 to 7.0, after run composer update and then try to check current version, I got error that required /symfony/polyfill-php56/bootstrap.php. My available symfony is polyfill-php72. How to change require polyfill-php56 to polyfill-php72?

This is my error look like

PHP Warning:  require(F:\Notes\Udemy\Laravel\Try\natusi\vendor\composer/../symfony/polyfill-php56/bootstrap.php): failed to open stream: No such file or directory in F:\Notes\Udemy\Laravel\Try\natusi\vendor\composer\autoload_real.php on line 66

This is my composer.json look like

{
"name": "laravel/laravel",
"type": "project",
"description": "The Laravel Framework.",
"keywords": [
    "framework",
    "laravel"
],
"license": "MIT",
"require": {
    "php": "^7.2.5",
    "fideloper/proxy": "^4.2",
    "laravel/framework": "^7.0",
    "maatwebsite/excel": "3.1.*",
    "laravel/tinker": "^2.0"
},
"require-dev": {
    "facade/ignition": "^2.0",
    "beyondcode/laravel-dump-server": "^1.0",
    "filp/whoops": "^2.0",
    "fzaninotto/faker": "^1.4",
    "mockery/mockery": "^1.0",
    "nunomaduro/collision": "^4.1",
    "phpunit/phpunit": "^8.5"
},
"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"
    ]
}}

via Chebli Mohamed