Bump xmlunit.version from 2.9.0 to 2.9.1

Bumps `xmlunit.version` from 2.9.0 to 2.9.1.

Updates `org.xmlunit:xmlunit-matchers` from 2.9.0 to 2.9.1
- [Release notes](https://github.com/xmlunit/xmlunit/releases)
- [Changelog](https://github.com/xmlunit/xmlunit/blob/main/RELEASE_NOTES.md)
- [Commits](xmlunit/xmlunit@v2.9.0...v2.9.1)

Updates `org.xmlunit:xmlunit-legacy` from 2.9.0 to 2.9.1
- [Release notes](https://github.com/xmlunit/xmlunit/releases)
- [Changelog](https://github.com/xmlunit/xmlunit/blob/main/RELEASE_NOTES.md)
- [Commits](xmlunit/xmlunit@v2.9.0...v2.9.1)

Updates `org.xmlunit:xmlunit-core` from 2.9.0 to 2.9.1
- [Release notes](https://github.com/xmlunit/xmlunit/releases)
- [Changelog](https://github.com/xmlunit/xmlunit/blob/main/RELEASE_NOTES.md)
- [Commits](xmlunit/xmlunit@v2.9.0...v2.9.1)

---
updated-dependencies:
- dependency-name: org.xmlunit:xmlunit-matchers
  dependency-type: direct:development
  update-type: version-update:semver-patch
- dependency-name: org.xmlunit:xmlunit-legacy
  dependency-type: direct:development
  update-type: version-update:semver-patch
- dependency-name: org.xmlunit:xmlunit-core
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

pom.xml

@@ -128,7 +128,7 @@
         <asm.version>9.6</asm.version>
 
         <!-- Test scope dependencies' versions -->
-        <xmlunit.version>2.9.0</xmlunit.version>
+        <xmlunit.version>2.9.1</xmlunit.version>
         <maven-plugin-plugin.version>3.10.2</maven-plugin-plugin.version>
         <shared-algorithms.version>0.12.0</shared-algorithms.version><!-- 0.13 require 11 -->
         <project.build.outputTimestamp>2022-04-20T23:14:54Z</project.build.outputTimestamp>