csstools/normalize missing during npm install on Ubuntu 18.04

[jmlon]

Cloned the repo, did the npm install (with a few failures), and after the npm start got this error message:
`Failed to compile.

./src/index.css (./node_modules/css-loader/dist/cjs.js??ref--6-oneOf-3-1!./node_modules/postcss-loader/src??postcss!./src/index.css)
Error: Cannot find module '@csstools/normalize.css'
`

Found a solution that worked for me:
npm remove csstools/normalize.css; npm install csstools/normalize.css

[moxiegirl]

@jmlon thanks for the note. I've changed the title to reflect the error so other folks can find this ticket.