Why the singleton implementation in C# 6.0 does not need the beforefieldinit flag?

I'm trying to understand why this is a correct implementation of the Singleton pattern:

public sealed class Singleton : ISingleton
{
    public static Singleton Instance { get; } = new Singleton();

    private Singleton() { }

    // methods
}

What about the beforefieldinit flag? According to Jon Skeet article:

The laziness of type initializers is only guaranteed by .NET when the type isn't marked with a special flag called beforefieldinit. Unfortunately, the C# compiler (as provided in the .NET 1.1 runtime, at least) marks all types which don't have a static constructor (i.e. a block which looks like a constructor but is marked static) as beforefieldinit.

Is the static constructor not needed in the newest version of C#?

The code above is the implementation of SystemClock in NodaTime project, by Jon Skeet.'

EDIT Jon Skeet code for reference (why I'm mentioning this beforefieldinit flag):

public sealed class Singleton
{
    private static readonly Singleton instance = new Singleton();

    // Explicit static constructor to tell C# compiler
    // not to mark type as beforefieldinit
    static Singleton()
    {
    }

    private Singleton()
    {
    }

    public static Singleton Instance
    {
        get
        {
            return instance;
        }
    }
}