updating the NOTICE (#3374)

diff --git a/NOTICE b/NOTICE
index e16c305..5e058ca 100644
--- a/NOTICE
+++ b/NOTICE
@@ -1,4 +1,4 @@
-Apache Heron
+Apache Heron (Incubating)
 Copyright 2018-2019 The Apache Software Foundation
 
 This product includes software developed at