laravel-image-optimizer conflicts with spatie/browsershot

Trying to install laravel-image-optimizer plugin I got errors:

$ composer require spatie/laravel-image-optimizer
Using version ^1.4 for spatie/laravel-image-optimizer
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Your requirements could not be resolved to an installable set of packages.

  Problem 1
    - The requested package spatie/browsershot (locked at 3.30.0, required as ^3.31) is satisfiable by spatie/browsershot[3.30.0] but these conflict with your requirements or minimum-stability.


Installation failed, reverting ./composer.json to its original content.

My composer.json :

{
    "name": "laravel/laravel",
    "description": "The Laravel Framework.",
    "keywords": ["framework", "laravel"],
    "license": "MIT",
    "type": "project",
    "require": {
        "php": "^7.1.3",
        "alaouy/youtube": "^2.2",
        "aloha/twilio": "^4.0",
        "arrilot/laravel-widgets": "^3.12",
        "beyondcode/laravel-websockets": "^1.0",
        "cviebrock/eloquent-sluggable": "^4.5",
        "davejamesmiller/laravel-breadcrumbs": "5.x",
        "doctrine/dbal": "^2.8",
        "elasticquent/elasticquent": "dev-master",
        "facebook/graph-sdk": "^5.7",
        "fideloper/proxy": "^4.0",
        "google/apiclient": "^2.2",
        "intervention/image": "^2.4",
        "itsgoingd/clockwork": "^3.0",
        "jrean/laravel-user-verification": "^7.0",
        "laravel/framework": "5.8.*",
        "laravel/socialite": "^3.2",
        "laravel/tinker": "^1.0",
        "laravelium/sitemap": "^3.1",
        "maatwebsite/excel": "^3.1",
        "mews/captcha": "^2.2",
        "mews/purifier": "^2.1",
        "proengsoft/laravel-jsvalidation": ">2.2.0",
        "pusher/pusher-php-server": "~3.0",
        "s-ichikawa/laravel-sendgrid-driver": "~2.0",
        "snowfire/beautymail": "dev-master",
        "socialiteproviders/instagram": "^3.0",
        "spatie/browsershot": "^3.31",
        "spatie/laravel-activitylog": "^3.1",
        "spatie/laravel-backup": "^6.1",
        "spatie/laravel-feed": "^2.1",
        "spatie/laravel-newsletter": "^4.2",
        "spatie/laravel-tags": "^2.1",
        "spipu/html2pdf": "^5.2",
        "themsaid/laravel-mail-preview": "^2.0",
        "unisharp/laravel-filemanager": "^1.9",
        "wboyz/laravel-enum": "^0.2.1",
        "willvincent/feeds": "1.1.*",
        "yajra/laravel-datatables-oracle": "^9.0.0"
    },
    "require-dev": {
        "barryvdh/laravel-debugbar": "^3.1",
        "filp/whoops": "^2.0",
        "fzaninotto/faker": "^1.4",
        "mockery/mockery": "^1.0",
        "nunomaduro/collision": "^2.0",
        "orangehill/iseed": "^2.6",
        "phpunit/phpunit": "^7.0",
        "xethron/migrations-generator": "^2.0"
    },
    "autoload": {
        "classmap": [
            "database/seeds",
            "database/factories"
        ],
        "psr-4": {
            "App\\": "app/"
        }
    },
    "autoload-dev": {
        "psr-4": {
            "Tests\\": "tests/"
        }
    },
    "extra": {
        "laravel": {
            "dont-discover": [
            ]
        }
    },
    "scripts": {
        "post-root-package-install": [
            "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
        ],
        "post-create-project-cmd": [
            "@php artisan key:generate"
        ],
        "post-autoload-dump": [
            "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump",
            "@php artisan package:discover"
        ],


        "post-update-cmd": [
            "php artisan vendor:publish --provider=\"Proengsoft\\JsValidation\\JsValidationServiceProvider\" --tag=public --force"
        ]

    },
    "config": {
        "preferred-install": "dist",
        "sort-packages": true,
        "optimize-autoloader": true
    },
    "minimum-stability": "dev",
    "prefer-stable": true
}

As I see here https://github.com/spatie/browsershot/releases latest version of it is 3.31.0

and it my composer.json I have

"spatie/browsershot": "^3.31",

is a latest version, just as on spatie/browsershot/releases page.

Which steps have I to take ?

Thanks!

via Chebli Mohamed