[Ignore] Update CHANGELOG.md to include PR #1158 (#1159)

Author: SydneyhSmith

CHANGELOG.md

@@ -21,6 +21,8 @@
   Simplify logic of determining Reference definition.
 - 🛫 🐛 [vscode-powershell #2379](https://github.com/PowerShell/PowerShellEditorServices/pull/1138) -
   Use -Option AllScope to fix Windows PowerShell error.
+- 👷 [PowerShellEditorServices #1158](https://github.com/PowerShell/PowerShellEditorServices/pull/1158) -
+ Sets the distribution channel env var to "PSES" so starts can be distinguished in PS7+ telemetry
 
 ## v2.0.0-preview.7
 ### Wednesday, December 11, 2019