[Bug] Webpack isn't marked as a transitive peer dependency

[JamesYeoman]

Describe the bug

Using the berry version of yarn, with the improved install logging that is default on the berry version, addon-postcss is being flagged as not providing webpack, which is a peer dependency for css-loader, postcss-loader, and style-loader.

Yarn even makes the error codes clickable to open the yarn docs page for the error code.

Steps to reproduce the behavior

Using the berry version of yarn, install @storybook/addon-postcss

Expected behavior

This package should declare webpack as a peer dependency, making it possible for yarn to hoist peer dependencies

Screenshots and/or logs

Environment

• OS: Windows 10
• Node.js version: v16.10.0
• Yarn version: v3.1.1 (yarn set version berry)