Incompatibility with .net core 3.0

[jonnybi]

Hosting EventFlow in a .net core 3.0 web application fails with this exception:

System.Reflection.ReflectionTypeLoadException: 'Unable to load one or more of the requested types.
Could not load type 'Microsoft.AspNetCore.Mvc.MvcJsonOptions' from assembly 'Microsoft.AspNetCore.Mvc.Formatters.Json, Version=3.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60'.'

It seems EventFlow having the same problems NSwag had with .net core 3.0
and caused by a reference to EventFlow.DependencyInjection
Create a .net core 3 web api application and add a reference to EventFlow.DependencyInjection to reproduce.

Similar issues:

• ASP.NET Core 3 support RicoSuter/NSwag#1961
• Missing type forward for JsonResult in ASP.NET Core 3.0? dotnet/aspnetcore#7220
• Incompatibility with ASP.NET Core 3.0 domaindrivendev/Swashbuckle.AspNetCore#1030

[ProH4Ck]

I'm working on it here: #686