chore(deps-dev): bump postcss in /example/svelte-kit

Bumps [postcss](https://github.com/postcss/postcss) from 8.3.8 to 8.4.47.
- [Release notes](https://github.com/postcss/postcss/releases)
- [Changelog](https://github.com/postcss/postcss/blob/main/CHANGELOG.md)
- [Commits](postcss/postcss@8.3.8...8.4.47)

---
updated-dependencies:
- dependency-name: postcss
  dependency-type: indirect
...

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Author: dependabot[bot]