build(deps): bump serenity-maven-plugin from 2.4.34 to 3.9.0

Bumps [serenity-maven-plugin](https://github.com/serenity-bdd/serenity-core) from 2.4.34 to 3.9.0.
- [Release notes](https://github.com/serenity-bdd/serenity-core/releases)
- [Changelog](https://github.com/serenity-bdd/serenity-core/blob/main/CHANGELOG.md)
- [Commits](serenity-bdd/serenity-core@v2.4.34...3.9.0)

---
updated-dependencies:
- dependency-name: net.serenity-bdd.maven.plugins:serenity-maven-plugin
  dependency-type: direct:production
  update-type: version-update:semver-major
...

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

activiti-cloud-acceptance-scenarios/pom.xml

@@ -33,7 +33,7 @@
     <java.version>1.${java.release}</java.version>
     <maven.compiler.release>${java.release}</maven.compiler.release>
     <activiti-cloud.version>7.9.0-alpha.29</activiti-cloud.version>
-    <serenity-maven-plugin.version>2.4.34</serenity-maven-plugin.version>
+    <serenity-maven-plugin.version>3.9.0</serenity-maven-plugin.version>
   </properties>
   <dependencyManagement>
     <dependencies>