added v8.4 changelogs

Author: ismcagdas

docs/en/Change-Logs.md

@@ -6,6 +6,11 @@ jQuery and ASP.NET Core + Angular versions beginning from v4.1. See
 
 The change logs in this page are just a summary of major changes. Detailed release notes are shared on the GitHub repository (only available to the customers).
 
+### v8.4.0 (2020-03-19)
+
+* Dynamic Entity Properties
+* User Delegation
+
 ### v8.3.1 (2020-03-06)
 
 * Fixed SignalR not defined error in MVC project.