Upgraded to Newtonsoft to 13

Author: Lachee

DiscordRPC/DiscordRPC.csproj

@@ -8,7 +8,7 @@
     <DocumentationFile>bin\$(Configuration)\$(TargetFramework)\$(AssemblyName).xml</DocumentationFile>
   </PropertyGroup>
   <ItemGroup>
-    <PackageReference Include="Newtonsoft.Json" Version="12.0.2" />
+    <PackageReference Include="Newtonsoft.Json" Version="13.0.1" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <PackageReference Include="Microsoft.SourceLink.GitHub" Version="1.1.1" PrivateAssets="All" />