ScssAsset: Parse for @imports and check if hasBeenModified

[juniwalk]

/**
 * @param  string  $file
 * @param  bool  $checkLastModified
 * @return bool
 */
public function hasBeenModified(string $file, bool $checkLastModified): bool
{
	if (!file_exists($file)) {
		return true;
	}

	if (!$checkLastModified) {
		return false;
	}

	// TODO: Parse for @imports and check those files too

	return filemtime($this->file) > filemtime($file);
}