/// Format a version based on its components
/// @access private
/// @param {Number} $major
/// @param {Number} $minor
/// @param {Number} $patch
/// @param {String} $pre-name ['']
/// @param {Number} $pre-number [-1]
/// @return {String}
@function _format($major, $minor, $patch, $pre-name: '', $pre-number: -1) {
  $release: $major + '.' + $minor + '.' + $patch;

  @if ($pre-number > -1) {
    $pre-name: $pre-name or '';
    $release: $release
      + '-'
      + $pre-name
      + if(str-length($pre-name) > 0, '.', '')
      + $pre-number;
  }

  @return $release;
}