Bump http-proxy-middleware and react-scripts in /examples/react-app

Bumps [http-proxy-middleware](https://github.com/chimurai/http-proxy-middleware) to 2.0.7 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 `http-proxy-middleware` from 0.19.1 to 2.0.7
- [Release notes](https://github.com/chimurai/http-proxy-middleware/releases)
- [Changelog](https://github.com/chimurai/http-proxy-middleware/blob/v2.0.7/CHANGELOG.md)
- [Commits](chimurai/http-proxy-middleware@v0.19.1...v2.0.7)

Updates `react-scripts` from 4.0.3 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-4.x.md)
- [Commits](https://github.com/facebook/create-react-app/commits/react-scripts@5.0.1/packages/react-scripts)

---
updated-dependencies:
- dependency-name: http-proxy-middleware
  dependency-type: indirect
- dependency-name: react-scripts
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>