Bump Newtonsoft.Json from 12.0.3 to 13.0.2 in /src/Memstate.JsonNet

Bumps [Newtonsoft.Json](https://github.com/JamesNK/Newtonsoft.Json) from 12.0.3 to 13.0.2.
- [Release notes](https://github.com/JamesNK/Newtonsoft.Json/releases)
- [Commits](JamesNK/Newtonsoft.Json@12.0.3...13.0.2)

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

Signed-off-by: dependabot[bot] <support@github.com>

src/Memstate.JsonNet/Memstate.JsonNet.csproj

@@ -24,7 +24,7 @@
     <Compile Remove="SurrogateConverter.cs" />
   </ItemGroup>
   <ItemGroup>
-    <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
   </ItemGroup>
   <ItemGroup>
     <ProjectReference Include="..\Memstate.Core\Memstate.Core.csproj" />