Laravel-excel: 2.1版本中未定义的类常量'XLSX'

我是第一次使用Maatwebsite / Laravel-Excel。

当我下载2.1版本时，cmd将显示

./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)
Nothing to install or update
Package phpoffice/phpexcel is abandoned, you should avoid using it. Use phpoffice/phpspreadsheet instead.
Generating optimized autoload files
> Illuminate\Foundation\ComposerScripts::postAutoloadDump
> <strong i="7">@php</strong> artisan package:discover

In excel.php line 59:

  Undefined class constant 'XLSX'


Script <strong i="8">@php</strong> artisan package:discover handling the post-autoload-dump event returned with error code 1

我不知道发生了什么事。
如果我下载2.0〜2.9，则cmd将显示安装失败。