composer VCS git fetch (extension or not does not matter here)

gistfile1.txt

Using:
project composer:
{
    "name": "pierre/testprj",
        "description": "Test prj for pickle",
        "license": "BSD",
        "authors": [
        {
            "name": "Pierre Joye",
            "email": "pierre.php@gmail.com"
        }
    ],
        "repositories": [
        {
            "type":"vcs",
            "url":"https://github.com/pierrejoye/igbinary"
        },
        {
            "packagist": false
        }
    ],
        "minimum-stability": "alpha",
        "require": {
            "pierrejoye/igbinary": "*"
        }
}

igbinary:
{
    "name": "igbinary",
    "version": "1.1.1",
    "type": "extension",
    "stability": "stable",
    "license": [
        "New BSD"
    ],
    "authors": [
        {
            "name": "Teddy Grenman",
            "email": "teddy.pecl@luuseri.com"
        }
    ],
    "description": "igbinary extension"
}