ASP.NET Core 3.1+ compatibility

[derigel23]

By default ASP.NET Core 3.0 doesn't use Newtonsoft JSON parser anymore. And all POC objects from bot annotated with Newtonsoft attributes are not deserializing correctly. Generally speaking ASP.NET Controller/Handler doesn't get any update from telegram server anymore.

[tuscen]

We're investigating options on how to add System.Text.Json support. Until then you can use Newtonsoft.Json formatter package in your web hooks:

services.AddMvc()
    .AddNewtonsoftJson();