[CONFIG] [NuGet] new JSON library added: Newtonsoft.Json.

Author: Gonzalo Diaz

algorithm_exercises_csharp_test/algorithm_exercises_csharp_test.csproj

@@ -32,6 +32,7 @@
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="17.11.0" />
     <PackageReference Include="MSTest.TestAdapter" Version="3.5.2" />
     <PackageReference Include="MSTest.TestFramework" Version="3.5.2" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
     <PackageReference Include="ReportGenerator" Version="5.3.8" />
   </ItemGroup>