composer install时报错

报错问题

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

  Problem 1
    - intervention/image 2.4.1 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.4.0 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.9 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.8 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.7 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.6 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.5 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.4 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.3 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.2 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.14 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.13 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.12 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.11 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.10 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.1 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.3.0 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.2.2 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.2.1 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - intervention/image 2.2.0 requires ext-fileinfo * -> the requested PHP extension fileinfo is missing from your system.
    - mews/captcha 2.2.0 requires intervention/image ~2.2 -> satisfiable by intervention/image[2.2.0, 2.2.1, 2.2.2, 2.3.0, 2.3.1, 2.3.10, 2.3.11, 2.3.12, 2.3.13, 2.3.14, 2.3.2, 2.3.3, 2.3.4, 2.3.5, 2.3.6, 2.3.7, 2.3.8, 2.3.9, 2.4.0, 2.4.1].
    - Installation request for mews/captcha ^2.2.0 -> satisfiable by mews/captcha[2.2.0].

  To enable extensions, verify that they are enabled in your .ini files:
    - /www/server/php/56/etc/php.ini
  You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.

解决方式：错误的原因是php.ini中的fileinfo扩展没有开启，开启 extension=php_fileinfo.dll