Update CONTRIBUTING.md (#1914)

clarified that the CoC is the one from the dotnetfoundation

Author: AlfredHellstern

CONTRIBUTING.md

@@ -1,11 +1,6 @@
 # Contributing
 
-This project has adopted the [Microsoft Open Source Code of
-Conduct](https://opensource.microsoft.com/codeofconduct/).
-For more information see the [Code of Conduct
-FAQ](https://opensource.microsoft.com/codeofconduct/faq/) or
-contact [opencode@microsoft.com](mailto:opencode@microsoft.com)
-with any additional questions or comments.
+This project has adopted the [.NET Foundation Code of Conduct](https://dotnetfoundation.org/about/policies/code-of-conduct).
 
 For our general contributing guidelines please see [our dotnet/runtime contributing guide](https://github.com/dotnet/runtime/blob/master/CONTRIBUTING.md).
 
@@ -25,4 +20,4 @@ This repository can be built on Windows, Linux, and OSX.
 
 Building, testing, and packing this repository can be done by using the standard dotnet CLI commands (e.g. `dotnet build`, `dotnet test`, `dotnet pack`, etc.).
 
-[VisualStudio]: https://docs.microsoft.com/dotnet/core/install/sdk?pivots=os-windows#install-with-visual-studio
+[VisualStudio]: https://docs.microsoft.com/dotnet/core/install/sdk?pivots=os-windows#install-with-visual-studio