Usage
  $ electron-builder <sourcedir> --platform=<platform> --config=<configPath> --out=<outputPath>

  Required options:
    platform:          win, osx, linux

  Optional options:
    config:            path to config file
                       -> if not provided `builder` property in `package.json`
                          in current working directory will be read
    out:               path to output the installer (path must exist)