Class 'League\Flysystem\AwsS3v3\AwsS3Adapter' not found (Laravel + Heroku)

I solved mine with

composer require guzzlehttp/psr7 "1.8.1"

to first downgrade from version 2.0.0 as the was sdk package doesn't yet support version 2.0.0.. then

composer require league/flysystem-aws-s3-v3 "~1.0" --update-with-all-dependencies

@localheinz When I did the deploy I run: composer install

But in heroku the packages install them from the console that has the heroku dashboard.

But when I want to add or remove the package league/flysystem-aws-s3-v3 the following message comes out:

Package listed for update is not installed. Ignoring.

So I think there's a cache in between, because everything works fine for me.

{
"name": "laravel/laravel",
"description": "The Laravel Framework.",
"keywords": ["framework", "laravel"],
"license": "MIT",
"type": "project",
"require": {
    "php": ">=5.6.4",
    "barryvdh/laravel-debugbar": "^2.4",
    "fzaninotto/faker": "^1.6",
    "laravel/framework": "5.4.*",
    "laravel/socialite": "^3.0",
    "laravel/tinker": "~1.0",
    "unisharp/laravel-ckeditor": "^4.6",
    "league/flysystem-aws-s3-v3": "~1.0"
},
"require-dev": {
    "mockery/mockery": "0.9.*"
},
"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
}
  }

For laravel 8 use

 composer require --with-all-dependencies league/flysystem-aws-s3-v3 "^1.0"

you forgot to install the required library

composer require league/flysystem-aws-s3-v3

good luck