报错信息：[Composer\Downloader\TransportException]
The "https://repo.packagist.org/p/doctrine/inflector.json" file could not be downloaded: fa
iled to open stream: HTTP request failed!
百度了好多，都没用，有的说是把镜像改成
composer config -g repo.packagist composer https://packagist.phpcomposer.com，我试了以后是没用的，后来把镜像换成阿里云的镜像就可以， 可能是因为镜像地址不稳定吧
改为：composer config -g repo.packagist composer https://mirrors.aliyun.com/composer/
即可
