Update date-fns and date-fns-tz to v3

[bsiguret]

Hello guys!

I was wondering if it's possible to upgrade date-fns and date-fns-tz to v3? We are currently using v-calendar and both date-fns packages on our project and we can't update those without having the two versions in our build due to v-calendar still on date-fns v2.

I can try to start a PR this way if it's ok for you.

The same issue applies to all packages to be honest.