Bump Newtonsoft.Json from 12.0.3 to 13.0.2 in /src/JT809.DotNetty.Core

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](https://github.com/JamesNK/Newtonsoft.Json/compare/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/JT809.DotNetty.Core/JT809.DotNetty.Core.csproj

@@ -29,7 +29,7 @@
     <PackageReference Include="JT809" Version="2.1.4-preview4" />
     <PackageReference Include="Microsoft.Extensions.Hosting.Abstractions" Version="3.1.4" />
     <PackageReference Include="Microsoft.Extensions.Options.ConfigurationExtensions" Version="3.1.4" />
-    <PackageReference Include="Newtonsoft.Json" Version="12.0.3" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.2" />
     <PackageReference Include="Microsoft.Extensions.Options" Version="3.1.4" />
     <PackageReference Include="Polly" Version="7.2.1" />
   </ItemGroup>