composer安装问题，改了中国镜像还是不行

Question

linux下执行升级命令，出现提示The"https://getcomposer.org/version"filecouldnotbedownloaded:failedtoopenstream:HTTPrequestfailed!root@linux:/opt/bitnami/apps/magento/htdocs#sudophp/opt/bitnami/php/bin/composer.pharself-update[Composer\Downloader\TransportException]The"https://getcomposer.org/version"filecouldnotbedownloaded:failedtoopenstream:HTTPrequestfailed!self-update[-r|--rollback][--clean-backups][version]查看/root/.composerconfig配置如下{"config":{},"repositories":[{"type":"composer","url":"http://pkg.phpcomposer.com/repo/packagist/"},{"packagist":false}]}我更改了config配置，这个是中国镜像，但是不知道怎么升级还是这个提示。