Update 2.13.1 release notes

Change-Id: I63cc731167722bec67815c2fb160ec3b2acda037
diff --git a/ReleaseNotes/ReleaseNotes-2.13.1.txt b/ReleaseNotes/ReleaseNotes-2.13.1.txt
index ef7e0e9..958e726 100644
--- a/ReleaseNotes/ReleaseNotes-2.13.1.txt
+++ b/ReleaseNotes/ReleaseNotes-2.13.1.txt
@@ -16,3 +16,6 @@
 
 * Fix internal server error when cloning from slaves and not all refs are
 visible.
+
+* Fix JSON deserialization error causing stream event client to no longer receive
+events.