Save the nupkg's as app veyor artifacts

Author: kevinkuszyk

appveyor.yml

@@ -15,4 +15,7 @@ build:
 
 test_script:
   - cmd: dotnet test samples\FluentAssertions.AspNetCore.Mvc.Sample.Tests\FluentAssertions.AspNetCore.Mvc.Sample.Tests.csproj
-  - cmd: dotnet test tests\FluentAssertions.AspNetCore.Mvc.Tests\FluentAssertions.AspNetCore.Mvc.Tests.csproj
+  - cmd: dotnet test tests\FluentAssertions.AspNetCore.Mvc.Tests\FluentAssertions.AspNetCore.Mvc.Tests.csproj
+
+artifacts:
+  - path: '**\*.nupkg'