Update DevExtreme NuGet feed URL with placeholder

Author: artem-kurchenko

ASP.NET Core/Nuget.config

@@ -2,6 +2,6 @@
 <configuration>
   <packageSources>
     <!-- Alternatively, use the DevExpress NuGet Feed: https://nuget.devexpress.com -->
-    <add key="devextreme-controls-netcore" value="https://nuget.devexpress.com/p66aZUkLxc6sQFZkESgwcLUcMlgCzAbGULQBqaY4bu2jivxKJ8/api/v3/index.json" />
+    <add key="devextreme-controls-netcore" value="https://nuget.devexpress.com/YOUR_KEY_HERE/api/v3/index.json" />
   </packageSources>
-</configuration>
+</configuration>