webpackDevServer task incompatible with the latest webpack-cli

[christiango]

If you bump a just task repo to the latest webpack-dev-server and webpack-cli, you'll get this error:
Error: Cannot find module 'webpack-cli/bin/config-yargs'

It seems like the guidance for starting a server is to no longer invoke webpack-dev-server like we do, but rather to call webpack serve
https://webpack.js.org/guides/development/

Here is a related issue on webpack-cli
webpack/webpack-cli#1948