Updating to dotnet.myget.org

Author: pranavkm

NuGet.config

@@ -2,7 +2,7 @@
 <configuration>
   <packageSources>
     <clear />
-    <add key="AspNetVNext" value="https://www.myget.org/f/aspnetmaster/api/v3/index.json" />
+    <add key="AspNetCore" value="https://dotnet.myget.org/F/aspnetcore-master/api/v3/index.json" />
     <add key="NuGet" value="https://api.nuget.org/v3/index.json" />
   </packageSources>
 </configuration>