提示信息:
The openssl extension is missing from the PHP version you specified.This means that
secure HTTPS transfers are not possible.
The recommended option is to enable the extension in your php.ini
解决方法：去PHP的安装地址找到php.ini，找到【extension=php_openssl.dll】，去掉前面的注释。然后在Composer退回上一步重新点击下一步。
