Fixes #4987 by updating the contribution guidelines link (#4988)

Author: koskila

CONTRIBUTING.md

@@ -2,5 +2,4 @@
 
 Thank you for your interest in contributing to the .NET documentation!
 
-This repository contains the API Reference .NET documentation. The main repository for .NET documentation is the [.NET Docs repository](https://github.com/dotnet/docs). See the [Contributing Guide](https://github.com/dotnet/docs/blob/master/CONTRIBUTING.md) for information on updating both .NET Docs conceptual and .NET API reference documentation.
-
+This repository contains the API Reference .NET documentation. The main repository for .NET documentation is the [.NET Docs repository](https://github.com/dotnet/docs). See the [Contributing Guide](https://docs.microsoft.com/contribute/dotnet/dotnet-contribute) for information on updating both .NET Docs conceptual and .NET API reference documentation.