Remove the index page for whats new and redirect to 3.0 whats new (#12675)

* redirected whats new to core 3.0

* Removed index for whats new in core

* fix build issue

* add updateeachrelease

Author: Thraka

docs/core/whats-new/index.md

@@ -1,23 +1,4 @@
 ---
-title: What's new in .NET Core
-description: Learn about the new features in each version of .NET Core.
-author: rpetrusha
-ms.author: ronpet
-ms.date: 02/04/2019
-ms.custom: seodec18
+redirect_url: dotnet-core-3-0
+ms.custom: updateeachrelease
 ---
-# What's new in .NET Core
-
-This page provides a summary of new features in each release of .NET Core starting with .NET Core 2.0. The following links provide detailed information on the major features added in each release.
-
-- [.NET Core 3.0 (Preview 2)](dotnet-core-3-0.md)
-
-- [.NET Core 2.2](dotnet-core-2-2.md)
-
-- [.NET Core 2.1](dotnet-core-2-1.md)
-
-- [.NET Core 2.0](dotnet-core-2-0.md)
-
-## See also
-
-- [What's new in ASP.NET Core 2.0](/aspnet/core/aspnetcore-2.0)

docs/toc.yml

@@ -185,7 +185,6 @@
   - name: Linux Prerequisites
     href: core/linux-prerequisites.md
   - name: What's new in .NET Core
-    href: core/whats-new/index.md
     items:
     - name: What's new in .NET Core 3.0
       href: core/whats-new/dotnet-core-3-0.md