lerp method

@override Border lerp(double t)

lerp return a value between begin and end

Implementation

@override
Border lerp(double t) => Border(
      top: BorderSide.lerp(begin.top, end.top, t),
      right: BorderSide.lerp(begin.right, end.right, t),
      bottom: BorderSide.lerp(begin.bottom, end.bottom, t),
      left: BorderSide.lerp(begin.left, end.left, t),
    );