Fix for ParallaxHeader grouped section headers appearing over the header, after cell recycling

ParallaxGroupedSectionHeaderTableView

public class ParallaxGroupedSectionHeaderTableView: UITableView {
    
    override public func layoutSubviews() {
        super.layoutSubviews()
        layoutHeaderViews()
    }
    
    private func layoutHeaderViews() {
        for index in 0 ..< numberOfSections {
            guard let sectionView = headerView(forSection: index) else { continue }
            self.sendSubview(toBack: sectionView)
        }
    }
}