Bump xmlunit-core from 2.8.2 to 2.8.3 in /fhir-parent

Bumps [xmlunit-core](https://github.com/xmlunit/xmlunit) from 2.8.2 to 2.8.3.
- [Release notes](https://github.com/xmlunit/xmlunit/releases)
- [Changelog](https://github.com/xmlunit/xmlunit/blob/main/RELEASE_NOTES.md)
- [Commits](xmlunit/xmlunit@v2.8.2...v2.8.3)

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

Signed-off-by: dependabot[bot] <support@github.com>

Author: dependabot[bot]

fhir-parent/pom.xml

@@ -214,13 +214,13 @@
             <dependency>
                 <groupId>org.xmlunit</groupId>
                 <artifactId>xmlunit-core</artifactId>
-                <version>2.8.2</version>
+                <version>2.8.3</version>
                 <scope>test</scope>
             </dependency>
             <dependency>
                 <groupId>com.google.code.gson</groupId>
                 <artifactId>gson</artifactId>
-                <version>2.8.8</version>
+                <version>2.8.9</version>
             </dependency>
             <dependency>
                  <!-- There are breaking changes in 10.15+ don't upgrade beyond this -->