Testing support for net6.0

NuGet.config

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?>
+<configuration>
+  <packageSources>
+    <add key="dotnet-tools" value="https://pkgs.dev.azure.com/dnceng/public/_packaging/dotnet-tools/nuget/v3/index.json" />
+    <add key="nuget" value="https://api.nuget.org/v3/index.json" /> 
+  </packageSources>
+</configuration>

Refit.Tests/InterfaceStubGenerator.cs

@@ -30,8 +30,10 @@ namespace Refit.Tests
 
         static InterfaceStubGeneratorTests()
         {
-#if NET5_0_OR_GREATER
+#if NET5_0
             ReferenceAssemblies = ReferenceAssemblies.Net.Net50;
+#elif NET6_0
+            ReferenceAssemblies = ReferenceAssemblies.Net.Net60;
 #else
             ReferenceAssemblies = ReferenceAssemblies.Default
                 .AddPackages(ImmutableArray.Create(new PackageIdentity("System.Text.Json", "6.0.1")));

Refit.Tests/Refit.Tests.csproj

@@ -19,7 +19,7 @@
     <PackageReference Include="System.Reactive" Version="5.0.0" />    
     <PackageReference Include="Microsoft.AspNetCore.WebUtilities" Version="2.2.0" />
     <PackageReference Include="Microsoft.CodeAnalysis.CSharp.Workspaces" Version="4.0.1" />
-    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.XUnit" Version="1.1.0" />
+    <PackageReference Include="Microsoft.CodeAnalysis.CSharp.SourceGenerators.Testing.XUnit" Version="1.1.1-beta1.22069.1" />
     <PackageReference Include="RichardSzalay.MockHttp" Version="6.0.0" />
     <ProjectReference Include="..\Refit.HttpClientFactory\Refit.HttpClientFactory.csproj" />
     <ProjectReference Include="..\Refit.Newtonsoft.Json\Refit.Newtonsoft.Json.csproj" />