refactor(core): small refactor

Add SchemaGeneratorFactory property to OpenApiDocumentGeneratorSettin…

…gs, RicoSuter#4524

Update NJS

Update NJS

Use supported versions of Microsoft.AspNetCore.* (RicoSuter#4561)

ASP.NET Core 2.1 on .NET Framework is supported
while version 2.2 is deprecated.

Update NJS/R

Merge branch 'master' of https://github.com/RicoSuter/NSwag

Set ChocolateyPush source

add axios abort signal (RicoSuter#4282)

* add axios abort signal

* unit test