* ensure that you can use Transition Child components
When you are using the implicit variants of the components, for example
when you are using a Transition component inside a Menu component then
it might look weird in Vue.
The Vue code could look like this:
```
<Menu>
<TransitionRoot>
<MenuItems>...</MenuItems>
</TransitionRoot>
<Menu>
```
However, `TransitionRoot` doesn't make much sense here because it sits
in the middle of 2 components, and it is also not controlled by an
explicit `show` prop.
This commit will allows you to use a `TransitionChild` instead (in fact,
both work).
We basically now do a few things, when you are using a TransitionChild:
- Do we have a parent `TransitionRoot`? Yes -> Use it
- Do we have an open closed state? Yes -> Render a TransitionRoot in
between behind the scenes.
- Throw the error we were throwing before!
* update changelog
Robin Malfait
e40c66cec2