Migrate to ARM Ubuntu18.04 node

Ubuntu 16.04 still has SSH and Kernel issues.
Migrating to Ubuntu18.04 since we have a good
instance now.

TODO: Disable Ubuntu16.04 arm nodes.
- Currently Ubuntu18.04 arm nodes are under more test.
- No additional costs since no job is using 16.04 arm
  nodes.
- Once confirmed, these will be disabled.

Change-Id: I1ef6dfc04aa6e85531f824e24ad517137a7080ca
Issue-ID: CIMAN-33
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
diff --git a/jjb/sdc/sdc-sdc-docker-base.yaml b/jjb/sdc/sdc-sdc-docker-base.yaml
index 6507f4f..10f087a 100644
--- a/jjb/sdc/sdc-sdc-docker-base.yaml
+++ b/jjb/sdc/sdc-sdc-docker-base.yaml
@@ -44,7 +44,7 @@
 #    mvn-settings: 'sdc-sdc-docker-base-settings'
 #    files: '**'
 #    archive-artifacts: ''
-#    build-node: ubuntu1604-docker-arm64-4c-2g
+#    build-node: ubuntu1804-docker-arm64-4c-2g
 #    maven-version: 'mvn35'
 
 - project: