Fix NuGet package security error

JamesNK · JamesNK · commit d8e2894b25b8 · 2021-06-18T17:39:59.000+12:00
diff --git a/src/GrpcHttpApi/sample/NuGet.config b/src/GrpcHttpApi/sample/NuGet.config
@@ -1,6 +1,7 @@
 ﻿<?xml version="1.0" encoding="utf-8"?>
 <configuration>
   <packageSources>
+    <clear />
     <add key="DotNet5 dev repository" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet5/nuget/v3/index.json" />
   </packageSources>
 </configuration>
