Have had intermittent issues with npm start
Diff made by
rm -rf node_modules rm package-lock.json npm i
This resolves dependency alerts and gives clean output from npm audit. However, we get a new polyfill issue from a dependency of crypto-browserify. Resolve this with
https://www.npmjs.com/package/node-polyfill-webpack-plugin
Updated https://www.npmjs.com/package/@testing-library/react to latest version to resolve mysterious test failures caused by dep upgrades.