Update support information (microsoft#1443)

Author: richlander

releases/README.md

@@ -14,9 +14,9 @@ You can see what was included in each .NET Framework release. Some releases are
 - [.NET Framework 4.7.1](net471/README.md)
 - [.NET Framework 4.7](net47/README.md)
 - [.NET Framework 4.6.2](net462/README.md)
-- [.NET Framework 4.6.1](net461/README.md)
-- [.NET Framework 4.6](net46/README.md)
-- [.NET Framework 4.5.2](net452/README.md)
+- [.NET Framework 4.6.1](net461/README.md) (unsupported)
+- [.NET Framework 4.6](net46/README.md) (unsupported)
+- [.NET Framework 4.5.2](net452/README.md) (unsupported)
 - [.NET Framework 4.5.1](net451/README.md) (unsupported)
 - [.NET Framework 4.5](https://blogs.msdn.microsoft.com/dotnet/2012/08/15/announcing-the-release-of-net-framework-4-5-rtm-product-and-source-code/) (unsupported)
 - [.NET Framework 4.0.3](https://blogs.msdn.microsoft.com/dotnet/2012/03/05/update-4-0-3-for-the-microsoft-net-framework-4/) (unsupported)