Bump org.gitlab4j:gitlab4j-api from 5.6.0 to 6.1.0

Bumps [org.gitlab4j:gitlab4j-api](https://github.com/gitlab4j/gitlab4j-api) from 5.6.0 to 6.1.0.
- [Release notes](https://github.com/gitlab4j/gitlab4j-api/releases)
- [Changelog](https://github.com/gitlab4j/gitlab4j-api/blob/main/CHANGELOG.md)
- [Commits](gitlab4j/gitlab4j-api@gitlab4j-api-5.6.0...6.1.0)

---
updated-dependencies:
- dependency-name: org.gitlab4j:gitlab4j-api
  dependency-version: 6.1.0
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

Author: dependabot[bot]

pom.xml

@@ -14,7 +14,7 @@
     <packaging>hpi</packaging>
 
     <properties>
-        <revision>5.6.0</revision>
+        <revision>6.1.0</revision>
         <changelist>999999-SNAPSHOT</changelist>
         <!-- https://www.jenkins.io/doc/developer/plugin-development/choosing-jenkins-baseline/ -->
         <jenkins.baseline>2.479</jenkins.baseline>