Removed flag to look for installed WIndows SDK when generating headers (#136)

Fixes #129 

We are already using the nuget version of the sdk, no need to also use
an installed version.

Co-authored-by: Nikola Metulev <[email protected]>

Author: nmetulev

src/winapp-CLI/WinApp.Cli/Services/CppWinrtService.cs

@@ -28,7 +28,6 @@ public async Task RunWithRspAsync(FileInfo cppwinrtExe, IEnumerable<FileInfo> wi
         var rspPath = new FileInfo(Path.Combine(outputDir.FullName, ".cppwinrt.rsp"));
 
         var sb = new StringBuilder();
-        sb.AppendLine("-input sdk+");
         foreach (var winmd in winmdInputs)
         {
             sb.AppendLine($"-input \"{winmd}\"");