• fix #219 fixing another 6 years old request we now automatically insert extra rows
  when dragging an item at the bottom below others to make it easier to insert below.
• fix #1687 more fix for drag between 2 grids with row / maxRow broken in 4.x
• fix export symbols .d.ts for gridstack-h5.js | gridstack-jq.js | gridstack-static.js
• fix #1709 correct info for using JQ version and ES6 (tested in Angular app)