removed sentence about migrating content (dotnet#4532)

* removed sentence about migrating content

* removed preview

README.md

@@ -2,7 +2,7 @@
 
 This repo contains work-in-progress documentation for .NET. To contribute, see the [Contributing Guide](https://github.com/dotnet/docs/blob/master/CONTRIBUTING.md) and the [issues list](https://github.com/dotnet/docs/issues). 
 
-We welcome contributions to help us improve and complete the .NET docs. Feel free to copy/paste documentation from [.NET Framework docs](https://msdn.microsoft.com/library/w0x726c2.aspx) as a starting point for .NET docs. We anticipate that [Xamarin](http://developer.xamarin.com/api/root/classlib/), [Mono](http://docs.go-mono.com/?link=root%3a%2fclasslib) and [Unity](http://docs.unity3d.com/Manual/index.html) will also use this documentation.
+We welcome contributions to help us improve and complete the .NET docs. We anticipate that [Xamarin](http://developer.xamarin.com/api/root/classlib/), [Mono](http://docs.go-mono.com/?link=root%3a%2fclasslib) and [Unity](http://docs.unity3d.com/Manual/index.html) will also use this documentation.
 
 This project has adopted the code of conduct defined by the Contributor Covenant
 to clarify expected behavior in our community.
@@ -11,7 +11,7 @@ For more information, see the [.NET Foundation Code of Conduct](https://dotnetfo
 Samples Build Status
 ===
 
-| Samples | Ubuntu 16.04<br/>_.NET Core 1.1.0_ | Ubuntu 16.04<br/>_.NET Core 2.0.0-preview_  |
+| Samples | Ubuntu 16.04<br/>_.NET Core 1.1.0_ | Ubuntu 16.04<br/>_.NET Core 2.0.0_  |
 | ------------- |------------| -----|
 | `/samples/core` | ![](https://constructors.visualstudio.com/_apis/public/build/definitions/3186585f-1677-4c9e-a8b2-baac48a4032a/56/badge)| ![](https://constructors.visualstudio.com/_apis/public/build/definitions/3186585f-1677-4c9e-a8b2-baac48a4032a/57/badge) |
 |`/samples/csharp`| ![](https://constructors.visualstudio.com/_apis/public/build/definitions/3186585f-1677-4c9e-a8b2-baac48a4032a/54/badge)| ![](https://constructors.visualstudio.com/_apis/public/build/definitions/3186585f-1677-4c9e-a8b2-baac48a4032a/55/badge) |