Bump Newtonsoft.Json in /developer_tools/vpnserver-jsonrpc-codegen

Bumps [Newtonsoft.Json](https://github.com/JamesNK/Newtonsoft.Json) from 11.0.2 to 13.0.1.
- [Release notes](https://github.com/JamesNK/Newtonsoft.Json/releases)
- [Commits](https://github.com/JamesNK/Newtonsoft.Json/compare/11.0.2...13.0.1)

---
updated-dependencies:
- dependency-name: Newtonsoft.Json
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

developer_tools/vpnserver-jsonrpc-codegen/vpnserver-jsonrpc-codegen.csproj

@@ -29,7 +29,7 @@
   <ItemGroup>
     <PackageReference Include="Markdig" Version="0.15.4" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp" Version="2.10.0" />
-    <PackageReference Include="Newtonsoft.Json" Version="11.0.2" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
   </ItemGroup>
 
 </Project>