Add voltha-system-test repo

Change-Id: I215b5d236ca806ac6bd985751d1d8adbcf94c7f5
diff --git a/default.xml b/default.xml
index 954521c..c467541 100644
--- a/default.xml
+++ b/default.xml
@@ -37,6 +37,7 @@
   <project path="voltha-protos" name="voltha-protos"/>
   <project path="voltha-simolt-adapter" name="voltha-simolt-adapter"/>
   <project path="voltha-simonu-adapter" name="voltha-simonu-adapter"/>
+  <project path="voltha-system-tests" name="voltha-system-tests"/>
   <project path="voltha-api-server" name="voltha-api-server"/>
   <project path="voltha-helm-charts" name="voltha-helm-charts"/>
 </manifest>