Create React App: Default linter and/or linting configuration cannot parse TypeScript's readonly modifier

See facebook/create-react-app#6420

git clone https://github.com/AlphaHydrae/create-react-app-typescript-readonly-bug.git && \
  cd create-react-app-typescript-readonly-bug && \
  npm ci && \
  ./node_modules/eslint/bin/eslint.js src/App.tsx