Update CHANGELOG for v3.7.3

Author: andyleejordan

CHANGELOG.md

@@ -1,5 +1,12 @@
 # PowerShell Editor Services Release History
 
+## v3.7.3
+### Wednesday, January 04, 2023
+
+- 🐛 🚂 [vscode-powershell #4343](https://github.com/PowerShell/PowerShellEditorServices/pull/1982) - Update VS Code shell integration script.
+- ✨ 🙏 [PowerShellEditorServices #1981](https://github.com/PowerShell/PowerShellEditorServices/pull/1981) - Make `Set-ScriptExtent` not slow.
+- 🐛 🙏 [PowerShellEditorServices #1959](https://github.com/PowerShell/PowerShellEditorServices/pull/1980) - Use an empty array instead of `null`.
+
 ## v3.7.2
 ### Tuesday, December 20, 2022