BUG: Focus trigger won't work / Wrong implementation

First of all, thanks for maintaining this plugin 😸 !

Since the `v-popover` wraps the trigger element within a div, if the given trigger is `focus` it won't work. Here's an example:

```html

```
Will turn into

```html

Therefore, the trigger is not being applied to the first element given within the `` component but to the wrapper instead, which in my opinion is wrong, otherwise the `focus` trigger doesn't make any sense if the focus will be applied to the wrapper instead to the desired element.

Running example: [https://jsfiddle.net/juanpablobl/yjt9asez/](https://jsfiddle.net/juanpablobl/yjt9asez/)

A nasty workaround would be firing the popover when clicking the input, but this goes against accessibility principles, moreover, I'm focusing the input as soon as the page loads in order to make the popover appear, but that won't happen because of what I just described.

Hope this information helps! Is there any way I could help or do you want me to provide further info? Thank you in advance!

Warm regards,
Juan Pablo

*PS: Also noticed that the class `trigger` is not scoped. If it doesn't, it should be something like `v-popover__trigger` instead just `trigger` to avoid class name collision with the parent project/website since `trigger` is quite a common word and it could be the case that there are global styles applied to that. Just saying 😅 *