allow no match

Author: harryhmc

azure/templates/deploy-service.yml

@@ -133,7 +133,7 @@ steps:
         export RELEASE_RELEASEID=$(Build.BuildId)
 
         echo "Setting assumed version"
-        ASSUMED_VERSION=`echo $SERVICE_ARTIFACT_NAME | grep -E -o "v[0-9]+\.[0-9]+\.[0-9]+-?[a-z]*" | tail -1`
+        export ASSUMED_VERSION=`echo $SERVICE_ARTIFACT_NAME | ( grep -E -o "v[0-9]+\.[0-9]+\.[0-9]+-?[a-z]*" || true ) | tail -1`
         echo "Setting deployed version"
         if [[ ! -z $ASSUMED_VERSION ]]; then
           echo "Setting deployed=assumed"