Feature/update readme (#157)

* Create dotnet.yml

* Updated the readme to point to geojson.text for system.text.json support

Co-authored-by: Martin Boje Carpentier <mbc@kamstrup.com>

Author: MartinCarpentier

README.md

@@ -28,15 +28,17 @@ Point point = JsonConvert.DeserializeObject<Point>(json);
 
 See the [Tests](https://github.com/GeoJSON-Net/GeoJSON.Net/tree/master/src/GeoJSON.Net.Tests) for more examples.
 
-## Special considerations for ASP.Net Core 3+
+## Special considerations for ASP.Net Core 3.1+
 
-System.Text.Json is the default (recommended) serializer. GeoJSON.Net **does not play well with System.Text.Json**. Here are the recommended steps as a workaround:
+System.Text.Json is the default (recommended) serializer. GeoJSON.Net **does not play well with System.Text.Json** and only supports Newtonsoft.Json
+
+[GeoJSON.Text](https://github.com/GeoJSON-Net/GeoJSON.Text) is a fork of this repository and have been developed to support System.Text.Json.
+
+If you still need to use Newtonsoft.Json in ASP.Net Core 3.1+, you must overwrite the default serializer.
 
 - add the "Microsoft.AspNetCore.Mvc.NewtonsoftJson" NuGet Package
 - add "services.AddControllers().AddNewtonsoftJson();" to your service configuration.
 
-(Thanks for @jrowe88 for pointing this out)
-
 ## Contributing
 Highly welcome! Just fork away and send a pull request. We try and review most pull requests within a couple of days. There is now a version 2.0.0 branch. I've created this ready for any breaking changes and any extra features and would encourage anything that isn't a bug fix to go in there.