Bump postcss-header from 3.0.1 to 3.0.3

Bumps [postcss-header](https://github.com/fengyuanchen/postcss-header) from 3.0.1 to 3.0.3.
- [Release notes](https://github.com/fengyuanchen/postcss-header/releases)
- [Changelog](https://github.com/fengyuanchen/postcss-header/blob/main/CHANGELOG.md)
- [Commits](https://github.com/fengyuanchen/postcss-header/compare/v3.0.1...v3.0.3

)

---
updated-dependencies:
- dependency-name: postcss-header
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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