Bump xmlunit-core from 2.6.3 to 2.6.4 (#6083)
Bump xmlunit-core from 2.6.3 to 2.6.4 (#6083)

Bumps [xmlunit-core](https://github.com/xmlunit/xmlunit) from 2.6.3 to 2.6.4.
- [Release notes](https://github.com/xmlunit/xmlunit/releases)
- [Changelog](https://github.com/xmlunit/xmlunit/blob/master/RELEASE_NOTES.md)
- [Commits](https://github.com/xmlunit/xmlunit/compare/v2.6.3...v2.6.4)

Signed-off-by: dependabot-preview[bot] <5bdcd3c0d4d24ae3e71b3b452a024c6324c7e4bb@dependabot.com>

Co-authored-by: dependabot-preview[bot] <6a4c1c4838f800d1998274cd5234e1f65c55e90c@users.noreply.github.com>
Siedlerchr/jabref,sauliusg/jabref,Siedlerchr/jabref,JabRef/jabref,sauliusg/jabref,JabRef/jabref,sauliusg/jabref,Siedlerchr/jabref,JabRef/jabref,sauliusg/jabref,Siedlerchr/jabref,JabRef/jabref