Add Vue 3 support

[loxK]

Versions

• vue: 3.0.4
• vue-datetime: 1.0.0-beta.14
• luxon: 1.25.0

Description:

Doesn't work, show a bunch of errors:

[Vue warn]: Property "$createElement" was accessed during render but is not defined on instance. 
  at <Datetime modelValue="" onUpdate:modelValue=fn >
  
[Vue warn]: Property "_self" was accessed during render but is not defined on instance. 
  at <Datetime modelValue="" onUpdate:modelValue=fn > 
  
[Vue warn]: Unhandled error during execution of render function 
  at <Datetime modelValue="" onUpdate:modelValue=fn > 
  
[Vue warn]: Unhandled error during execution of scheduler flush. This is likely a Vue internals bug. Please open an issue at https://new-issue.vuejs.org/?repo=vuejs/vue-next 
  at <Datetime modelValue="" onUpdate:modelValue=fn > 

Uncaught (in promise) TypeError: _vm._self is undefined
    render webpack:///./node_modules/vue-datetime/dist/vue-datetime.js?:697

[gofish543]

@loxK In the future, read other issues posted on a Git repo before making your own. I'd also focus on wording, your issue comes across sounding very entitled, remember this is an open source project which you can submit code to.

@mariomka Do you have any plans on getting this package to be Vue 3 compatible? If so, do you need help? If not, would you be willing to accept pull requests to get this package Vue 3 compatible?

[nirnejak]

+1 for Vue 3 Support