Updating OS Image for Integration Build

Changing build image from CENTOS to Ubuntu in relation to builds failing
for netconf pnp simulator on using invalid python libraries
Ticket - https://jira.linuxfoundation.org/plugins/servlet/theme/portal/2/IT-23574?sda_source=notification-email

Issue-ID: CPS-816
Change-Id: Ie55100bdf2fca34761fd4fbe8efca3c2ab08ec5d
Signed-off-by: DylanB95EST <dylan.byrne@est.tech>
diff --git a/jjb/integration/integration-docker.yaml b/jjb/integration/integration-docker.yaml
index da2b798..8a4cf0d 100644
--- a/jjb/integration/integration-docker.yaml
+++ b/jjb/integration/integration-docker.yaml
@@ -43,7 +43,7 @@
         # To simplify the references inside tox.ini and tests/settings.py
         docker tag "$CONTAINER_PUSH_REGISTRY/$DOCKER_NAME:$DOCKER_IMAGE_TAG" netconf-pnp-simulator:latest
         tox
-    build-node: centos7-docker-8c-8g
+    build-node: ubuntu1804-docker-8c-8g
     build-timeout: 20
     jobs:
       - gerrit-docker-verify