* ensure there is an animatable root node
This is a bit sad, but it is how Vue works...
We used to render just a simple PopoverPanel that resolved to let's say
a `<div>`, that's all good. Because the native `<transition>` component
requires that there is only 1 DOM child (regardless of the Vue "tree").
This is the sad part, because we simplified focus trapping for the
Popover by introducing sibling hidden buttons to capture focus instead
of managing this ourselves.
Since we can't just return multiple items we wrap them in a `Fragment`
component.
If you wrap items in a Fragment, then a lot of Vue's magic goes away
(automatically adding `class` to the root node). Luckily, Vue has a
solution for that, which is `inheritAttrs: false` and then manually
spreading the `attrs` onto the correct element.
This all works beautiful, but not for the `<transition>` component...
so... let's move the focus trappable elements inside the actual Panel
and update the logic slightly to go to the Next/Previous item instead of
the First/Last because the First/Last will now be the actual focus guards.
* update changelog
* make TypeScript a bit happier
* improve `default` slot in `PopoverPanel`
Robin Malfait
255fc36668