Laravel Framework Upgrade 5.4 -> ^6|^7|^8

I want to Update my Laravel Project. And I already run this code on my project terminal

composer update laravel/framework

but I just get Info Like this

Loading composer repositories with package information
Info from https://repo.packagist.org: #StandWithUkraine
Updating dependencies
Nothing to modify in lock file
Installing dependencies from lock file (including require-dev)
Nothing to install, update or remove
Package jakub-onderka/php-console-color is abandoned, you should avoid using it. Use php-parallel-lint/php-console-color instead.                                                                                                                 
Package jakub-onderka/php-console-highlighter is abandoned, you should avoid using it. Use php-parallel-lint/php-console-highlighter instead.                                                                                                     
Package maddhatter/laravel-fullcalendar is abandoned, you should avoid using it. No replacement was suggested.
Package mtdowling/cron-expression is abandoned, you should avoid using it. Use dragonmantank/cron-expression instead.    
Package swiftmailer/swiftmailer is abandoned, you should avoid using it. Use symfony/mailer instead.
Package fzaninotto/faker is abandoned, you should avoid using it. No replacement was suggested.
Package phpunit/php-token-stream is abandoned, you should avoid using it. No replacement was suggested.
Package phpunit/phpunit-mock-objects is abandoned, you should avoid using it. No replacement was suggested.
Generating optimized autoload files
Carbon 1 is deprecated, see how to migrate to Carbon 2.
https://carbon.nesbot.com/docs/#api-carbon-2
    You can run ".\vendor\bin\upgrade-carbon" to get help in updating carbon and other frameworks and libraries that depend on it.
33 packages you are using are looking for funding.
Use the `composer fund` command to find out more!
> Illuminate\Foundation\ComposerScripts::postUpdate
> php artisan optimize
Generating optimized class loader
The compiled services file has been removed.

and this is my composer.json

{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"license": "MIT",
"type": "project",
"require": {
    "php": ">=5.6.4",
    "almasaeed2010/adminlte": "~3.1",
    "ecasanes/laravel-google-calendar-php-6": "^1.1",
    "guzzlehttp/guzzle": "^7.4",
    "intervention/image": "^2.7",
    "laravel/framework": "5.4.*",
    "laravel/tinker": "~1.0",
    "maddhatter/laravel-fullcalendar": "^1.3",
    "uxweb/sweet-alert": "^2.0"
},
"require-dev": {
    "fzaninotto/faker": "~1.4",
    "mockery/mockery": "0.9.*",
    "phpunit/phpunit": "~5.7"
},
"autoload": {
    "classmap": [
        "database"
    ],
    "psr-4": {
        "App\\": "app/"
    }
},
"autoload-dev": {
    "psr-4": {
        "Tests\\": "tests/"
    }
},
"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",
    "sort-packages": true,
    "optimize-autoloader": true
}}

I want to upgrade my Project min to Laravel ^6 to use composer require barryvdh/laravel-dompdf

but after Edit "laravel/framework": "^8.0" and "phpunit/phpunit": "^9.0", I got error message like this

Loading composer repositories with package information
Info from https://repo.packagist.org: #StandWithUkraine
Updating dependencies
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - Root composer.json requires phpunit/phpunit ^9.0, found phpunit/phpunit[9.0.0, ..., 9.5.19] but the package is fixed to 5.7.27 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command.
  Problem 2
    - laravel/framework[v8.0.0, ..., v8.83.5] require monolog/monolog ^2.0 -> found monolog/monolog[2.0.0, ..., 2.4.0] but the package is fixed to 1.27.0 (lock file version) by a partial update and that version does not match. Make sure you list it as an argument for the update command.
    - Root composer.json requires laravel/framework ^8.0 -> satisfiable by laravel/framework[v8.0.0, ..., v8.83.5].      

Use the option --with-all-dependencies (-W) to allow upgrades, downgrades and removals for packages currently locked to specific versions.

I already stuck in this step. I can't move to next step from my project. thank you

via Chebli Mohamed