Use vue demi to support Vue2 and Vue3

[sduduzog]

What kind of change does this PR introduce?

Chore: A conditional check for a VueJS version. This attempts to use https://github.com/vueuse/vue-demi as mentioned in #2

What is the current behavior?

Package only supports use in VueJS V2

What is the new behavior?

• Includes support for Vue3
• Exposes useSupabase possible through the provide/inject api
• For Vue 2.x users will have to also install @vue/composition-api

Additional context

This has been manually tested against a Vue 2.x, Vue 3.x (with vue cli and vite) and a nuxt project with a nuxt-supabase fork

[sduduzog]

Finally comfortable with this PR @scottrobertson

I also updated the README with the changes in usage

[scottrobertson]

Thanks @sduduzog.

I am guessing there is no way around having to use @vue/composition-api for Vue2 users? Since that is quite the breaking change. If not, it's fine as I can just tag this as 2.x but yeah... would be awesome if we can find a way without.

@NuroDev do you have any suggestions around that?

[NuroDev]

Nope, all looks good to me 👍🏻

[scottrobertson]

Nope, all looks good to me 👍🏻

Thank you.

@sduduzog have you done any integration testing already for Nuxt-Supabase yet or should I do that?

[sduduzog]

@scottrobertson I have, in a private repo. All works well, still with the composition-api being a prerequisite.

[sduduzog]

I still recommend you test too, I'll create a PR for nuxt-supabase with this branch