Just as things begin to thaw between Harry and William, Meghan’s ongoing battle with her older half-sister, Samantha Markle, is heating up. Over the years, Samantha, 56, has thrown all sorts of shade at Meghan, criticizing her for cutting off their father, Thomas, and for not inviting family members to her 2018 wedding to Harry, among other things. But she may have saved the best for last as she gears up to release her tell-all book, The Diary of Princess Pushy’s Sister — Part 1, on Jan. 17. “Meghan isn’t the least bit surprised,” says an insider of the upcoming memoir. “She knew this was coming.” Another source says the former actress is likely to adopt a stiff upper lip about it. “Of course it bothers Meghan privately, but she…
