Update CHANGELOG for v2.4.3

Author: andyleejordan

CHANGELOG.md

@@ -1,5 +1,11 @@
 # PowerShell Editor Services Release History
 
+## v2.4.3
+### Wednesday, May 26, 2021
+
+-  [PowerShellEditorServices #1491](https://github.com/PowerShell/PowerShellEditorServices/pull/1491) - Bump OmniSharp to `v0.19.2`.
+- 🧠🐛 [vscode-powershell #715](https://github.com/PowerShell/PowerShellEditorServices/pull/1484) - Fix unintentional module import. (Thanks @MartinGC94!)
+
 ## v2.4.2-preview.1
 ### Friday, May 21, 2021