Bump loader-utils and react-scripts in /03-defining-classes/d-refs

Bumps [loader-utils](https://github.com/webpack/loader-utils) to 2.0.3 and updates ancestor dependency [react-scripts](https://github.com/facebook/create-react-app/tree/HEAD/packages/react-scripts). These dependencies need to be updated together.


Updates `loader-utils` from 0.2.17 to 2.0.3
- [Release notes](https://github.com/webpack/loader-utils/releases)
- [Changelog](https://github.com/webpack/loader-utils/blob/v2.0.3/CHANGELOG.md)
- [Commits](webpack/loader-utils@v0.2.17...v2.0.3)

Updates `react-scripts` from 1.1.4 to 5.0.1
- [Release notes](https://github.com/facebook/create-react-app/releases)
- [Changelog](https://github.com/facebook/create-react-app/blob/main/CHANGELOG-1.x.md)
- [Commits](https://github.com/facebook/create-react-app/commits/react-scripts@5.0.1/packages/react-scripts)

---
updated-dependencies:
- dependency-name: loader-utils
  dependency-type: indirect
- dependency-name: react-scripts
  dependency-type: direct:production
...

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