misc: update changelog

Change-Id: Id7c2fe35449b253147a9c237eb846a1cfd2cee56

changelog.md

+# 2020-03-16
+
+## Bug Fixes
+
++ Fixed the bug that the system notification cannot be disabled
++ Fixed video device enumeration for higher framerates
++ More reliable high dpi adaption
++ Prevent crash when video device events happen with no account
+
+## New Features
+
++ Add type indicator
++ Movable splitter in main view
++ Connectivity improvement for calls and messages
+
 # 2019-12-13
 
 ## Bug Fixes