用composer 创建thinkphp项目，环境是php8.1.21，创建thinkphp6项目成功，创建thinkphp8项目时出现下面错误：

Updating dependencies

Your requirements could not be resolved to an installable set of packages.

  Problem 1

    - league/flysystem[2.0.0, ..., 2.5.0] require league/mime-type-detection ^1.0.0 -> satisfiable by league/mime-type-detection[1.0.0, ..., 1.11.0].

    - topthink/think-filesystem[v2.0.0, ..., v2.0.1] require topthink/framework ^6.1 -> found topthink/framework[v6.1.0, ..., v6.1.4] but it conflicts with your root composer.json require (^8.0).

    - league/mime-type-detection[1.0.0, ..., 1.3.0] require php ^7.2 -> your php version (8.1.21) does not satisfy that requirement.

    - league/mime-type-detection[1.4.0, ..., 1.11.0] require ext-fileinfo * -> it is missing from your system. Install or enable PHP's fileinfo extension.

    - topthink/think-filesystem v2.0.2 requires league/flysystem ^2.0 -> satisfiable by league/flysystem[2.0.0, ..., 2.5.0].

    - Root composer.json requires topthink/think-filesystem ^2.0 -> satisfiable by topthink/think-filesystem[v2.0.0, v2.0.1, v2.0.2].

To enable extensions, verify that they are enabled in your .ini files:

    - D:\php\php.ini

You can also run `php --ini` in a terminal to see which files are used by PHP in CLI mode.

Alternatively, you can run Composer with `--ignore-platform-req=ext-fileinfo` to temporarily ignore these required extensions.

解决方法：
出现此错误的原因是php.ini中的fileinfo扩展没有开启，开启 extension=fileinfo，再重新执行命令安装就可以了。

也就是把 php.ini里面的  ;extension=fileinfo 这一句前面分号去掉，开启了就可以了。