Release v1.5.0

Added support for FrameworkPropertyMetadataOptions flags.
These flags may be specified with or without a property's default value, allowing for usage like...

// 👩‍💻 user

// No default value is provided, will be implemented using the default value for the generic type argument.
// In this case: `default(string?)` (which resolves to `null`).
public static readonly DependencyProperty TextProperty = Gen.Text<string?>(
    FrameworkPropertyMetadataOptions.BindsTwoWayByDefault);

// Default value argument is provided, as well as a flags argument.
public static readonly DependencyProperty ErrorBrushProperty = GenAttached.ErrorBrush<Brush>(
    Brushes.Red,
    FrameworkPropertyMetadataOptions.Inherits);