Target 2.1 for Microsoft.Extensions.Configuration (#467)

src/Microsoft.Tye.Extensions.Configuration/Microsoft.Tye.Extensions.Configuration.csproj

@@ -5,7 +5,7 @@
   </PropertyGroup>
 
   <ItemGroup>
-    <PackageReference Include="Microsoft.Extensions.Configuration.KeyPerFile" Version="3.1.3" />
+    <PackageReference Include="Microsoft.Extensions.Configuration" Version="2.1.1" />
   </ItemGroup>
 
 </Project>

test/E2ETest/testassets/projects/multi-project/worker/Program.cs

@@ -5,7 +5,6 @@
 using System;
 using System.IO;
 using Microsoft.Extensions.Configuration;
-using Microsoft.Extensions.Configuration.KeyPerFile;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;