Upgrades NuGet packages for enhanced features

Updates NuGet.Protocol to the latest stable version and adds Newtonsoft.Json package.

This ensures compatibility with the latest NuGet features and adds JSON handling capabilities, enabling more robust and efficient processing.

Author: Keboo

generator/DocGenerator.csproj

@@ -9,7 +9,8 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="NuGet.Protocol" Version="6.12.1" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.3" />
+    <PackageReference Include="NuGet.Protocol" Version="6.14.0" />
   </ItemGroup>
 
   <ItemGroup>