Update to work with Webpack 5
Update to work with Webpack 5

Changed "Webpack-dev-server" to "webpack serve" to work with Webpack 5.
Changed the material importer to be put under 'sassOptions' rather than just options. Similar with the autoprefixer; put it under postcssOptions under options. 
Don't have issues going through the Getting Started walkthrough now
material-components/material-components-web,material-components/material-components-web,material-components/material-components-web