Композитор: Может установить только одно из: minishlink / web-push [v4.0.0, dev-master]

Я пытаюсь установить web-push (https://github.com/web-push-libs/web-push-php) в Ubuntu 14, но с помощью компоновщика выполнения требуется minishlink / web-push, я получаю следующую ошибку:

Problem 1:
- Can only install one of: minishlink/web-psuh[v4.0.0, dev-master].
- Can only install one of: minishlink/web-psuh[v4.0.1, dev-master].
- Can only install one of: minishlink/web-psuh[v4.0.2, dev-master].
- Installation request for minishlink/web-push dev-master -> Satisfiable by minishlink/web-push[dev-master].
- Installation request for minishlink/web-push ^4.0 -> satisfiable by minishlink/web-push[v4.0.0, v4.0.1, v4.0.2].

Composer.json

    {
"name": "minishlink/web-push",
"type": "library",
"description": "Web Push library for PHP",
"keywords": ["push", "notifications", "web", "WebPush", "Push API"],
"homepage": "https://github.com/web-push-libs/web-push-php",
"license": "MIT",
"authors": [
{
"name": "Louis Lagrange",
"email": "[email protected]",
"homepage": "https://github.com/Minishlink"}
],
"require": {
"minishlink/web-push": "^4.0"},
"require-dev": {
"phpunit/phpunit": "^7.0"}
}