The topic to which to publish the notification.
If no value is specified then the default value ("jenkins/$JOB_URL" e.g. "jenkins/job/my-build") is used.
The following variables can also be used (prefix with "$"):
- BUILD_RESULT - The result of the build (e.g. SUCCESS, FAILURE, ABORTED, etc.)
- PROJECT_URL - The job project's URL (e.g. "job/my-build")
- CULPRITS - Comma-separated list of the culprits responsible for the current build result