Request yarn support for friendly error alerts

[hellojukay]

For own npm repositories, what if I let yarn install support output error messages? For example, if a package has a serious security issue and the server blocks the installation during yarn installation, yarn should output a friendly error message.

body.error or body.message should be printed.

[hellojukay]

https://github.com/yarnpkg/yarn/blob/master/src/util/request-manager.js#L520