Migrate HELM jobs to Ubuntu18

Migrate to ubuntu1804-helm-2c-1g

Change-Id: I5b8e73ec6ce11c56076ef940a8df45700e99ef7a
Issue-ID: CIMAN-373
Signed-off-by: Jessica Wagantall <jwagantall@linuxfoundation.org>
diff --git a/jjb/oom/oom-helm.yaml b/jjb/oom/oom-helm.yaml
index c276629..5868f9f 100644
--- a/jjb/oom/oom-helm.yaml
+++ b/jjb/oom/oom-helm.yaml
@@ -6,7 +6,7 @@
     mvn-settings: oom-settings
     mvn-global-settings: global-settings
     archive-artifacts: ''
-    build-node: ubuntu1604-helm-2c-1g
+    build-node: ubuntu1804-helm-2c-1g
     pre_build_script: !include-raw-escape: shell/helm-repo-init.sh
     oom_build_script: |
         #!/bin/bash