How to install package in old laravel project

I have a project built in laravel 5.8 and I want to add socialite package in this project but whenever I try to install the socialite package it gave me this error all the time. Here is my composer.json

{
"name": "laravel/laravel",
"type": "project",
"description": "The Laravel Framework.",
"keywords": [
    "framework",
    "laravel"
],
"license": "MIT",
"require": {
    "php": "^7.1.3",
    "anandsiddharth/laravel-paytm-wallet": "^1.0",
    "anhskohbo/no-captcha": "^3.1",
    "barryvdh/laravel-dompdf": "^0.8.6",
    "caouecs/laravel-lang": "~4.0",
    "cartalyst/stripe-laravel": "10.*",
    "doctrine/dbal": "^2.10",
    "fideloper/proxy": "^4.0",
    "guzzlehttp/guzzle": "~6.0",
    "instamojo/instamojo-php": "^0.4.0",
    "laravel/framework": "5.8.*",
    "laravel/socialite": "^5.0",
    "laravel/tinker": "^1.0",
    "masterro/laravel-xss-filter": "^1.0",
    "mollie/laravel-mollie": "2.0",
    "paypal/rest-api-sdk-php": "^1.14",
    "phpmailer/phpmailer": "^6.1",
    "rachidlaasri/laravel-installer": "^4.1",
    "razorpay/razorpay": "2.*",
    "renatomarinho/laravel-page-speed": "^1.8",
    "softon/indipay": "^1.2",
    "spatie/laravel-cookie-consent": "^2.10",
    "spatie/laravel-sitemap": "^5.7",
    "willvincent/feeds": "^2.1"
},
"require-dev": {
    "beyondcode/laravel-dump-server": "^1.0",
    "filp/whoops": "^2.0",
    "fzaninotto/faker": "^1.4",
    "mockery/mockery": "^1.0",
    "nunomaduro/collision": "^3.0",
    "phpunit/phpunit": "^7.5"
},
"config": {
    "optimize-autoloader": true,
    "preferred-install": "dist",
    "sort-packages": true
},
"extra": {
    "laravel": {
        "dont-discover": []
    }
},
"autoload": {
    "psr-4": {
        "App\\": "app/"
    },
    "classmap": [
        "database/seeds",
        "database/factories"
    ],
    "files": ["app/Http/Helpers/Helper.php"]
},
"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"
    ]
}

Note: I am using PHP Version 7.4 with laragon
Please help me to solve this problem.
Thanks in Advance

via Chebli Mohamed