update dmaap mr UBuntu buld nodes to 18.04

Issue-ID: DMAAP-1414
Change-Id: I9651637fe73c33ebba417965cb856665dae9cf28
Signed-off-by: su622b <su622b@att.com>
diff --git a/jjb/dmaap/dmaap-messagerouter-msgrtr.yaml b/jjb/dmaap/dmaap-messagerouter-msgrtr.yaml
index 90baffd..2d872f7 100644
--- a/jjb/dmaap/dmaap-messagerouter-msgrtr.yaml
+++ b/jjb/dmaap/dmaap-messagerouter-msgrtr.yaml
@@ -30,7 +30,7 @@
     sonarcloud-project-key: '{sonarcloud_project_organization}_{project-name}'
     sonar-mvn-goal: '{sonar_mvn_goal}'
     cron: '@daily'
-    build-node: ubuntu1604-builder-4c-4g
+    build-node: ubuntu1804-builder-4c-4g
     project: 'dmaap/messagerouter/msgrtr'
     project-name: 'dmaap-messagerouter-msgrtr'
     branch: 'master'