title: Items on collectionview appears twice after device rotation
body: <p>I have a items (buttons, labels) on cells on my uicollectionview. As soon as I rotate my device items appears twice.... I already called viewWillTransition but no effect, always the same issue.. Any idea ? Thanks! Here is my code : </p>
  
  <pre><code>override func viewDidLayoutSubviews() {
      super.viewDidLayoutSubviews()
  
      collectionView.collectionViewLayout.invalidateLayout()
      collectionView.layoutIfNeeded()
  }
  
  public override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
      super.viewWillTransition(to: size, with: coordinator)
  
      coordinator.animate(alongsideTransition: { (context) in
          self.collectionView.collectionViewLayout.invalidateLayout()
  
      }, completion: nil)
  }
  </code></pre>