Things to be reverted in time

[JamieDixon]

1. packages/react-scripts/fixtures/kitchensink/src/features/webpack/assets/style.css

Need to uncomment /*@import '~normalize.css/normalize.css';*/ once we stop using postcss in V3. This is commented because we've told webpack to import all CSS from paths.appSrc + '/assets/stylesheets/common' which causes CRA e2e tests to fail because they can't find the normalize file as expected.

Test with: tasks/e2e-kitchensink.sh

2. packages/react-scripts/fixtures/kitchensink/integration/webpack.test.js

Need to uncomment tests:

    it('css inclusion', async () => {
      const doc = await initDOM('css-inclusion');
    
      expect(
        doc.getElementsByTagName('style')[0].textContent.replace(/\s/g, '')
      ).to.match(/html\{/);
      expect(
        doc.getElementsByTagName('style')[1].textContent.replace(/\s/g, '')
      ).to.match(/#feature-css-inclusion\{background:.+;color:.+}/);
    });

This is part of the above change to fix CSS imports.