Install .NET 6 SDK to enable XAML Styler after removal from

 `windows-latest` Actions CI image.

See also actions/runner-images#12241

Author: Arlodotexe

.github/workflows/build.yml

@@ -34,6 +34,12 @@ jobs:
 
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
+      # .NET 6 SDK is required for xamlstyler.console to run.
+      - name: Install .NET SDK v6
+        uses: actions/setup-dotnet@v4
+        with:
+          dotnet-version: 6.0.x
+
       - name: Install .NET SDK v${{ env.DOTNET_VERSION }}
         uses: actions/setup-dotnet@v4
         with: