Do you want to request a feature or report a bug?
bug

What is the current behavior?
you can install webpack-cli witghout webpack and get no warning

If the current behavior is a bug, please provide the steps to reproduce.
npm install webpack-cli on an empty project

What is the expected behavior?
An npm peer requirement warning

If this is a feature request, what is motivation or use case for changing the behavior?

Please mention other relevant information such as the browser version, Node.js version, Operating System and programming language.