NuGet package targets .NET 4.6.1 only

[dgrechka]

Adding the Angara.Base nuget package fails with
Could not install package 'Angara.Serialization 0.1.2'. You are trying to install this package into a project that targets '.NETFramework,Version=v4.5',but the package does not contain any assembly references or content files that are compatible with that framework. For more information, contact the package author.
for frameworks: 4.0, 4.5, 4.5.1, 4.5.2, 4.6

Works only targeting 4.6.1