Bump react-native from 0.63.4 to 0.64.1 in /example

Bumps [react-native](https://github.com/facebook/react-native) from 0.63.4 to 0.64.1.
- [Release notes](https://github.com/facebook/react-native/releases)
- [Changelog](https://github.com/facebook/react-native/blob/main/Releases.md)
- [Commits](facebook/react-native@v0.63.4...v0.64.1)

---
updated-dependencies:
- dependency-name: react-native
  dependency-type: direct:production
...

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Author: dependabot[bot]