Updating to release NuGet.config

NuGet.Config

@@ -1,7 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <packageSources>
-    <add key="AspNetVNext" value="https://www.myget.org/F/aspnetvnext/api/v2" />
+    <clear />
+    <add key="AspNetVNext" value="https://www.myget.org/F/aspnetrelease/api/v2" />
     <add key="NuGet" value="https://nuget.org/api/v2/" />
   </packageSources>
 </configuration>