feat: add Vue 3 support

[crutch12]

Custom directives breaking changed:
https://v3.vuejs.org/guide/migration/custom-directives.html#custom-directives

[dacoto97]

Hi @simplesmiler,
The new version of vue 3 has already been released, are there plans to make this plugin compatible?

[garyzoar]

I am also interested in this being vue 3 compatible.

[StarkShang]

I also need this support for vue 3.0

[VinceG]

@crutch12 @dacoto97 @StarkShang @garyzoar
https://github.com/VinceG/vue-click-away