webman:captcha库报错

一，报错代码:

        // 验证码长度
        $length = 4;
        // 包含哪些字符
        $chars = '0123456789abcefghijklmnopqrstuvwxyz';
        $builder = new PhraseBuilder($length, $chars);
        $captcha = new CaptchaBuilder(null, $builder);

        // 生成验证码
        $captcha->build($width = 200, $height = 80, $font = null);
        // 将验证码的值存储到session中
        $request->session()->set('captcha', strtolower($captcha->getPhrase()));

        // 获得验证码图片二进制数据
        $img_content = $captcha->get();
        return response($img_content, 200, ['Content-Type' => 'image/jpeg']);

报错信息:

ErrorException: Webman\Captcha\CaptchaBuilder::__construct(): Implicitly marking 
parameter $builder as nullable is deprecated, the explicit nullable type must be used 
instead in /web/vendor/webman/captcha/src/CaptchaBuilder.php:143
Stack trace:

问题原因:

php8不允许直接使用null作为参数，

二，解决:

修改:

/web/vendor/webman/captcha/src/CaptchaBuilder.php:143

内容:

public function __construct($phrase = null, ?PhraseBuilderInterface $builder = null)

说明：在此一行增加了一个？

这个有更好的解决方法吗？请大家提供一下