Bump git-changelist-maven-extension from 1.4 to 1.6

Bumps [git-changelist-maven-extension](https://github.com/jenkinsci/incrementals-tools) from 1.4 to 1.6.
- [Release notes](https://github.com/jenkinsci/incrementals-tools/releases)
- [Commits](jenkinsci/incrementals-tools@parent-1.4...parent-1.6)

---
updated-dependencies:
- dependency-name: io.jenkins.tools.incrementals:git-changelist-maven-extension
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

.mvn/extensions.xml

@@ -2,6 +2,6 @@
   <extension>
     <groupId>io.jenkins.tools.incrementals</groupId>
     <artifactId>git-changelist-maven-extension</artifactId>
-    <version>1.4</version>
+    <version>1.6</version>
   </extension>
 </extensions>