update README.md about SixLabors.ImageSharp

Author: IldarKhayrutdinov

README.md

@@ -2,9 +2,7 @@
 
 **PdfSharpCore** is a partial port of [PdfSharp.Xamarin](https://github.com/roceh/PdfSharp.Xamarin/) for .NET Standard
 Additionally MigraDoc has been ported as well (from version 1.32).
-Images have been implemented with [ImageSharp](https://github.com/JimBobSquarePants/ImageSharp/), which is still in Alpha. They State on their readme that it is still in Alpha status and shouldn't be used in productive environments. Since I didn't find any good alternatives it's still used.
-
-ImageSharp being Alpha isn't a big issue either since this code isn't by far done yet. So please chime in ;)
+Images have been implemented with [ImageSharp](https://github.com/SixLabors/ImageSharp), which has a stable status.
 
 **PdfSharp.Xamarin** is a partial port of [PdfSharp](http://www.pdfsharp.net/) for iOS and Android using Xamarin, it allows for creation and modification of PDF files.