Update CHANGELOG-EE.md for 13.1.6-ee

[ci skip]

CHANGELOG-EE.md

@@ -376,6 +376,10 @@ Please view this file on the master branch, on stable branches it's out of date.
 - Resolve duplicate use of shorcuts-tree. !36732
+## 13.1.6 (2020-08-05)
+
+- No changes.
+
 ## 13.1.5 (2020-07-23)
 ### Fixed (2 changes)