Bump slevomat/coding-standard from 8.28.0 to 8.28.1

Bumps [slevomat/coding-standard](https://github.com/slevomat/coding-standard) from 8.28.0 to 8.28.1.
- [Release notes](https://github.com/slevomat/coding-standard/releases)
- [Commits](slevomat/coding-standard@8.28.0...8.28.1)

---
updated-dependencies:
- dependency-name: slevomat/coding-standard
  dependency-version: 8.28.1
  dependency-type: direct:development
  update-type: version-update:semver-patch
...

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Author: dependabot[bot]