composer 失败 [ 2.0 版本 ]

插件下载不成功

D:\phpStudy\www\yii\a>composer require --prefer-dist spanjeta/yii2-backup "*"
The "yiisoft/yii2-composer" plugin was skipped because it requires a Plugin API
version ("1.0.0") that does not match your Composer installation ("1.1.0"). You
may need to run composer update with the "--no-plugins" option.
./composer.json has been updated
The "yiisoft/yii2-composer" plugin was skipped because it requires a Plugin API
version ("1.0.0") that does not match your Composer installation ("1.1.0"). You
may need to run composer update with the "--no-plugins" option.
Loading composer repositories with package information
Updating dependencies (including require-dev)
Reading bower.json of bower-asset/fontawesome (v4.3.0)