message: Migrate to use new Shader Model API
  The currently used method, SetShaderModel has been deprecated in
  favour of SetHLSLShaderModel. This CL migrates Dawn, so that the
  deprecated method can be removed from upstream.
diff: @@ -33,7 +33,7 @@ namespace {
  // Using the options that are used by Dawn, they appear in ShaderModuleD3D12.cpp
  options.SetFlipVertY(true);
  - options.SetShaderModel(51);
  + options.SetHLSLShaderModel(51);
  compiler.CompileSpvToHlsl(input.data(), input.size(), options);
  });
  