fix versioning (#4115)

Author: ryfu-msft

hub/package-manager/winget/index.md

@@ -40,9 +40,9 @@ $progressPreference = 'silentlyContinue'
 Write-Information "Downloading WinGet and its dependencies..."
 Invoke-WebRequest -Uri https://aka.ms/getwinget -OutFile Microsoft.DesktopAppInstaller_8wekyb3d8bbwe.msixbundle
 Invoke-WebRequest -Uri https://aka.ms/Microsoft.VCLibs.x64.14.00.Desktop.appx -OutFile Microsoft.VCLibs.x64.14.00.Desktop.appx
-Invoke-WebRequest -Uri https://github.com/microsoft/microsoft-ui-xaml/releases/download/v2.7.3/Microsoft.UI.Xaml.2.7.x64.appx -OutFile Microsoft.UI.Xaml.2.7.x64.appx
+Invoke-WebRequest -Uri https://github.com/microsoft/microsoft-ui-xaml/releases/download/v2.8.6/Microsoft.UI.Xaml.2.8.x64.appx -OutFile Microsoft.UI.Xaml.2.8.x64.appx
 Add-AppxPackage Microsoft.VCLibs.x64.14.00.Desktop.appx
-Add-AppxPackage Microsoft.UI.Xaml.2.7.x64.appx
+Add-AppxPackage Microsoft.UI.Xaml.2.8.x64.appx
 Add-AppxPackage Microsoft.DesktopAppInstaller_8wekyb3d8bbwe.msixbundle
 ```