场景复现：

本地 phpstudy 环境，安装的有7.0到7.3三个版本，首先确认composer已经安装

composer安装阿里云oss的命令为：composer require aliyuncs/oss-sdk-php

运行报错：

 Problem 1
    - Root composer.json requires php ^7.2.5 but your php version (7.0.3) does not satisfy that requirement.
  Problem 2
    - gonoware/laravel-maps is locked to version v1.3.1 and an update of this package was not requested.
    - gonoware/laravel-maps v1.3.1 requires php ^7.2|^7.2.5 -> your php version (7.0.3) does not satisfy that requirement.

但是我查了本地项目运行环境的确是7.3，后来察觉可能是环境变量问题，结果一查果然环境变量指定的php是7.0目录，修改为7.3

关闭cmd，重新打开cmd面板，切换至项目根目录，执行composer命令，完美运行。