Create nuget.config (#127)

Author: angelazhangmsft

Samples/nuget.config

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- This file was added for building in the CI pipeline. It is not used when building locally. -->
+<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>
+    <clear />
+        <add key="nuget.org" value="https://api.nuget.org/v3/index.json" />
+    </packageSources>
+    <disabledPackageSources />
+</configuration>