use <major>-<distro> instead of latest

Signed-off-by: MarkAckert <mark.ackert@broadcom.com>

container/Dockerfile

@@ -10,19 +10,19 @@
 #######################################################################
 
 # base image tag
-ARG ZOWE_BASE_IMAGE=latest-ubuntu
+ARG ZOWE_BASE_IMAGE=3-ubuntu
 
 FROM zowe-docker-release.jfrog.io/ompzowe/base-node:${ZOWE_BASE_IMAGE} AS builder
 
 ##################################
 # labels
 LABEL name="USS Explorer" \
-      maintainer="jack-tiefeng.jia@ibm.com" \
-      vendor="Zowe" \
-      version="0.0.0" \
-      release="0" \
-      summary="IBM z/OS Unix Files UI service" \
-      description="This Zowe UI component can display unix files on z/OS"
+    maintainer="jack-tiefeng.jia@ibm.com" \
+    vendor="Zowe" \
+    version="0.0.0" \
+    release="0" \
+    summary="IBM z/OS Unix Files UI service" \
+    description="This Zowe UI component can display unix files on z/OS"
 
 ##################################
 # switch context