add one known issue

update release note to add one known issue

Issue-ID: CLAMP-840

Change-Id: Icf970dc3473e51161e11159ad16a4ae50ff6312d
Signed-off-by: osgn422w <gervais-martial.ngueko@intl.att.com>
diff --git a/docs/release-notes.rst b/docs/release-notes.rst
index a557b4d..6f9e41a 100644
--- a/docs/release-notes.rst
+++ b/docs/release-notes.rst
@@ -33,6 +33,7 @@
 	- The full list of issues(bugs) solved, is available on `CLAMP R6 - Frankfurt list of solved issues(bugs) <https://wiki.onap.org/pages/viewpage.action?pageId=84648915>`_
 
 **Known Issues**
+    - `CLAMP-856 <https://jira.onap.org/browse/CLAMP-856>`_ CLAMP should not display all CDS workflow properties
 
 
 **Security Notes**