fix nuget.config

nuget.config

@@ -1,7 +1,13 @@
 <?xml version="1.0" encoding="utf-8"?>
 <configuration>
+  <packageRestore>
+    <!-- Allow NuGet to download missing packages -->
+    <add key="enabled" value="True" />
+    <!-- Automatically check for missing packages during build in Visual Studio -->
+    <add key="automatic" value="True" />
+  </packageRestore>
+
   <packageSources>
-    <add key="nuget.org" value="https://www.nuget.org/api/v2/"/>
-    <add key="nuget (SimpleStubs)" value="NuGet"/>
+    <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
   </packageSources>
 </configuration>