Fix DNN Featurizer sample bug. (#3237)

Author: codemzs

docs/samples/Microsoft.ML.Samples/Microsoft.ML.Samples.csproj

@@ -187,4 +187,18 @@
     <PackageReference Include="Microsoft.ML.Onnx.TestModels" Version="$(MicrosoftMLOnnxTestModelsVersion)" />
   </ItemGroup>
 
+    <ItemGroup>
+    <Content Include="$(ObjDir)DnnImageModels\ResNet18Onnx\ResNet18.onnx">
+      <Link>DnnImageModels\ResNet18Onnx\ResNet18.onnx</Link>
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+  
+    <ItemGroup>
+    <Content Include="$(ObjDir)DnnImageModels\ResNetPrepOnnx\ResNetPreprocess.onnx">
+      <Link>DnnImageModels\ResNetPrepOnnx\ResNetPreprocess.onnx</Link>
+      <CopyToOutputDirectory>PreserveNewest</CopyToOutputDirectory>
+    </Content>
+  </ItemGroup>
+  
 </Project>