Replace all Ubuntu 16.04 with Ubuntu18.04 image
Change-Id: I86b84957145f7c1f253d3158e42e015c322788eb
diff --git a/jjb/verify/voltha-protos.yaml b/jjb/verify/voltha-protos.yaml
index aefda8b..14ebf9a 100644
--- a/jjb/verify/voltha-protos.yaml
+++ b/jjb/verify/voltha-protos.yaml
@@ -19,7 +19,7 @@
- 'verify-licensed'
- 'tag-collision-reject':
- 'make-unit-test':
- build-node: 'ubuntu16.04-basebuild-2c-4g'
+ build-node: 'ubuntu18.04-basebuild-2c-4g'
build-timeout: 20
unit-test-targets: 'test'
unit-test-keep-going: 'true'