如何解决此错误“无法将要求解决为一组可安装的软件包”。

Question

我是composer的新手，当尝试通过composer安装Bogdaan / viber-bot-php时，我遇到了此问题“您的要求无法解决为一组可安装的软件包。”

这是控制台输出。

C:\xampp\htdocs\viber-api>composer require bogdaan/viber-bot-php dev-master
./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 bogdaan/viber-bot-php No version set (parsed as 1.0.0) is satisfiable by bogdaan/viber-bot-php[No version set (parsed as 1.0.0)] but these conflict with your requirements or minimum-stability.


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

这是我的composer.json

{
    "name": "bogdaan/viber-bot-php",
    "description": "Php bot interface to work with Viber API",
    "keywords": ["viber", "im", "bot"],
    "type": "library",
    "license": "MIT",
    "authors": [
        {
            "name": "Novikov Bogdan",
            "email": "hcbogdan@gmail.com"
        }
    ],
    "require": {
        "php": ">=5.5.0",
        "guzzlehttp/guzzle": "^6.2"
    },
    "autoload": {
        "psr-4": {
            "Viber\\": "src/"
        }
    },
    "require-dev": {
        "phpunit/phpunit": "^4.8",
        "monolog/monolog": "^1.22"
    }
}