Bump xmlunit-assertj3 from 2.8.4 to 2.9.0

Bumps [xmlunit-assertj3](https://github.com/xmlunit/xmlunit) from 2.8.4 to 2.9.0.
- [Release notes](https://github.com/xmlunit/xmlunit/releases)
- [Changelog](https://github.com/xmlunit/xmlunit/blob/main/RELEASE_NOTES.md)
- [Commits](https://github.com/xmlunit/xmlunit/compare/v2.8.4...v2.9.0

)

---
updated-dependencies:
- dependency-name: org.xmlunit:xmlunit-assertj3
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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