Bump Microsoft.AspNetCore.Mvc.NewtonsoftJson from 3.1.5 to 3.1.6 in /core/diagnostics/DiagnosticScenarios (#3732)

* Bump Microsoft.AspNetCore.Mvc.NewtonsoftJson

Bumps [Microsoft.AspNetCore.Mvc.NewtonsoftJson](https://github.com/aspnet/AspNetCore) from 3.1.5 to 3.1.6.
- [Release notes](https://github.com/aspnet/AspNetCore/releases)
- [Changelog](https://github.com/dotnet/aspnetcore/blob/master/docs/CrossRepoBreakingChanges.md)
- [Commits](dotnet/aspnetcore@v3.1.5...v3.1.6)

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

* Update to 3.1 LTS

Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Bill Wagner <[email protected]>

Author: dependabot[bot]

core/diagnostics/DiagnosticScenarios/DiagnosticScenarios.csproj

@@ -1,11 +1,11 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>netcoreapp3.0</TargetFramework>
+    <TargetFramework>netcoreapp3.1</TargetFramework>
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.1.5" />
+    <PackageReference Include="Microsoft.AspNetCore.Mvc.NewtonsoftJson" Version="3.1.6" />
   </ItemGroup>
 
 </Project>