react-scripts@2 final blockers

Created by: gaearon

Let's just keep track in one list so we don't forget.

Code Blockers

• Fix runtime issues (https://github.com/facebook/create-react-app/issues/5116)
• CSS bug? https://github.com/facebook/create-react-app/issues/5140
• Give bundle analyzer thing final testing and make a decision (https://github.com/facebook/create-react-app/issues/4563#issuecomment-425193592)
• Switch to Babel loader (https://github.com/facebook/create-react-app/issues/5122#issuecomment-425192725)
• Fix EPIPE noise on failed builds. https://github.com/facebook/create-react-app/issues/5138
• Check that it works on Node 10 https://github.com/facebook/create-react-app/issues/5103#issuecomment-425637128
  • new apps work on node 10, running yarn upgrade before upgrading react-scripts would probably fix this, or we can file a bug with yarn
• Check if this is a regression https://github.com/facebook/create-react-app/issues/5164
• Investigate migration path for https://github.com/facebook/create-react-app/issues/5178
• Why does Workbox output have so many files? And what is Google Analytics doing there? https://github.com/facebook/create-react-app/pull/4169#issuecomment-425684363
• Fix or document class properties regression with Flow https://github.com/facebook/create-react-app/issues/5176#issuecomment-425721254
• Stretch: nicer webpack messages (can also go in a patch)
• Include license into packages https://github.com/facebook/create-react-app/issues/4944

Docs Blockers

• Remove anything outdated from the User Guide
• Make a decent changelog and migration guide from 1.x

Docs Follow-ups

• Ping Ives https://github.com/facebook/create-react-app/issues/5128
• Document /* autoprefixer grid: on */ for CSS grid
• Update React's "Add React to Website" JSX section
• Prepare blog post
• Document Workbox (https://github.com/facebook/create-react-app/pull/5111)
• Make a decent migration guide from 2.x betas
  • Monorepo migration (https://github.com/facebook/create-react-app/issues/5100)
• Check and document Apollo (https://github.com/facebook/create-react-app/issues/5126) and Relay support
• Explain browserslist https://github.com/facebook/create-react-app/pull/3644#issuecomment-425231139
• MDX https://github.com/facebook/create-react-app/issues/5149
• All the other stuff in https://github.com/facebook/create-react-app/issues/5127