Add the following Groovy script:
def env = manager.build.getEnvironment(); if(manager.build.result.isBetterOrEqualTo(hudson.model.Result.UNSTABLE) && "true".equals(env['IS_M2RELEASEBUILD'])) { manager.addShortText("${manager.build.buildVariables.get('MVN_RELEASE_VERSION')}") }
After performing a maven release the build history looks like this: