Update PowerShell version to 7.6-preview.4

Author: sdwheeler

reference/docs-conceptual/whats-new/What-s-New-in-PowerShell-76.md

@@ -13,7 +13,7 @@ For a complete list of changes, see the [CHANGELOG][04] in the GitHub repository
 
 ## Updated modules
 
-PowerShell 7.6-preview.3 includes the following updated modules:
+PowerShell 7.6-preview.4 includes the following updated modules:
 
 - **Microsoft.PowerShell.PSResourceGet** v1.1.0
 - **PSReadLine** v2.3.6