在 composer.json 我输入"nex/yii2-datepicker" : "*"了 require 部分并且最低稳定性是稳定的。现在我运行composer update，然后显示foll错误
Loading composer repositories with package information
Updating dependencies (including require-dev)
Content-Length mismatch
http://packagist.org could not be fully loaded, package information was loaded from the local cache and may be out of date
Your requirements could not be resolved to an installable set of packages.
问题 1 - 请求的包 nex/yii2-datepicker * 可以满足 nex/yii2-datepicker[dev-master] 但这些与您的要求或最低稳定性相冲突