Mention Serilog.Extensions.Hosting in the readme

[BobVul]

Currently, the readme mentions two scenarios:

• ASP.NET Core 2.0+ => Serilog.AspNetCore
• .NET Core 1.0, 1.1 => Serilog.Extensions.Logging

It makes no mention of the best approach for .NET Core 2.x and 3.x applications that do not use ASP.NET. From what I can tell, Serilog.Extensions.Hosting is the recommended package in this case, but it takes some digging through issues to find; it's not listed in the Serilog.AspNetCore readme either.

Please consider including a section in the readme pointing towards to recommended approach for non-ASP .NET Core 2.x/3.x projects.

[nblumhardt]

Done - thanks!

[BobVul]

Thanks!