fix: explicitly add key in Children.map because preact does not copy key (and React does it).

Author: meowtec

packages/react-swipeable-views/src/SwipeableViews.js

@@ -828,6 +828,7 @@ So animateHeight is most likely having no effect at all.`,
 
               return (
                 <div
+                  key={child.key}
                   ref={ref}
                   style={slideStyle}
                   className={slideClassName}