[DCAE] Add istanbul branch for CLM jobs

Change-Id: I833d0ebe8e0c55241a913e71cc0c5140e0e81a80
Signed-off-by: vv770d <vv770d@att.com>
Issue-ID: DCAEGEN2-3060
Signed-off-by: vv770d <vv770d@att.com>
diff --git a/jjb/dcaegen2/dcaegen2-platform-mod-designtool.yaml b/jjb/dcaegen2/dcaegen2-platform-mod-designtool.yaml
index 255817d..fc8539c 100644
--- a/jjb/dcaegen2/dcaegen2-platform-mod-designtool.yaml
+++ b/jjb/dcaegen2/dcaegen2-platform-mod-designtool.yaml
@@ -33,5 +33,9 @@
     project: dcaegen2/platform
     build-node: ubuntu1804-docker-8c-8g
     project-name: 'dcaegen2-platform-mod-designtool'
-    branch: 'master'
+    stream:
+      - 'master':
+          branch: 'master'
+      - 'istanbul':
+          branch: 'istanbul'
     mvn-settings: 'dcaegen2-platform-settings'