Migrating vue-debounce to vue3

[dhershman1]

I know it's been a hot minute but the migration is finally here, just going to do some more testing and would love more eyes on this PR if anyone gets a chance.

Breaking Changes

• Remove support for Vue 2
  • If you need to continue supporting Vue2 please switch to the vue2-debounce package or stay of v4 of this one
• vue-debounce is now registered as a ES module instead of a cjs package
  • This helps the transition over to Vue3
  • This will help keep the typing system clean
• CDN Support is no longer guaranteed with the package being a module now

Fixed

• README now reflects how to use vue-debounce with only vue3