Twelve South has announced an updated version of its BookArc for iPad, which now touts compatibility with the iPad mini ($30). An arc-shaped, steel stand first released three years ago, BookArc for iPad now also comes with silicone inserts to hold an iPad mini, as well as prior-generation iPads. For those who already own a BookArc for iPad and only want the rubber inserts to hold the iPad mini, Twelve South announced plans to offer the inserts separately…