README.md is Innacurate

https://github.com/browserify/path-browserify#install

The statement about Webpack including node.js polyfill code is no longer accurate as of Webpack 5, per [this documentation](https://webpack.js.org/blog/2020-10-10-webpack-5-release/#automatic-nodejs-polyfills-removed). Some packages now **require** external polyfills like this one even when using Webpack if they are using the newest version.