Bump org.exist-db:exist-core from 5.4.0 to 6.3.0

Bumps [org.exist-db:exist-core](https://github.com/exist-db/exist) from 5.4.0 to 6.3.0.
- [Release notes](https://github.com/exist-db/exist/releases)
- [Changelog](https://github.com/eXist-db/exist/blob/develop/exist-versioning-release.md)
- [Commits](eXist-db/exist@eXist-5.4.0...eXist-6.3.0)

---
updated-dependencies:
- dependency-name: org.exist-db:exist-core
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

pom.xml

@@ -48,7 +48,7 @@
         <project.build.source>1.8</project.build.source>
         <project.build.target>1.8</project.build.target>
 
-        <exist.java-api.version>5.4.0</exist.java-api.version>            <!-- The eXist-db XQuery Java Module API version -->
+        <exist.java-api.version>6.3.0</exist.java-api.version>            <!-- The eXist-db XQuery Java Module API version -->
         <exist.processor.version>6.1.0</exist.processor.version>          <!-- The version of eXist-db needed by this EXPath Module -->
 
         <jackson.version>2.18.2</jackson.version>