How to include package branch from github???

composer.json

{
  "require": {
    "fortawesome/font-awesome": "dev-master"
  },
  "repositories": [
    "type": "package",
    "package": {
        "name": "fortawesome/font-awesome",
        "version": "master",
        "source": {
            "url": "https://github.com/FortAwesome/Font-Awesome.git",
            "type": "git",
            "reference": "3.1.0-wip"
        }
    }
  ]
}

this produces the following error

  [RuntimeException]
  Failed to execute git checkout '3.1.0-wip' && git reset --hard '3.1.0-wip'

  error: pathspec '3.1.0-wip' did not match any file(s) known to git.