fastadmin composer更新提示： 

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

  Problem 1
    - overtrue/wechat 4.2.11 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - overtrue/wechat 4.2.11 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - overtrue/wechat 4.2.11 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - Installation request for overtrue/wechat 4.2.11 -> satisfiable by overtrue/wechat[4.2.11].

  To enable extensions, verify that they are enabled in your .ini files:
    - C:\phpStudy\PHPTutorial\php\php-7.2.1-nts\php.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

解决办法：

开启php的php_fileinfo扩展即可