feat: support .sync modifier

[jefrydco]

Fix #15

[koca]

Hey, thanks for the PR.
But why do we need the sync modifier? If the default v-model events solves the problem than lets use value prop and input event instead of code prop and change event.
What do you think?

[jefrydco]

Yes, I agree with you. My consideration is if we change the code prop and change event, it would be a breaking change. Because they are the main communication between this package and the rest of the world.

And themodel options in your component declaration already solved the problem as well, isn't it?

[koca]

Yep you are right that would be a breaking change. I will merge this and we can release removed version with v1.0.0? Sounds good?

[jefrydco]

I will merge this and we can release removed version with v1.0.0?

You mean that we can change thecode props and change event with value props and input event, then release them with v1.0.0? If it yes, sounds good to me.

[koca]

Actually I was thinking about two options:
1 - merge this and publish v0.4.0. (this evening)
2 - merge this and publish v0.4.0 and remove .sync on the v1.0.0 release (I'm planining to release next weekend).

I'll go with the second option. I'm merging this and releasing a new version. Next week v1.0.0 i will deprecate for the sake of proper v-model.