fix: main useMemo, add dependency on currentDatetime

[weissleb]

Description

My use case, which feels pretty common, has me wanting the timezone options to update when the currentDatetime changes. So if we include a date picker in our app and the user chooses a date in which the timezones switch from standard to daylight, the options in the select update automatically.

Linked Issues

More detail, and an updated example can be found in this forked branch. I also opened an enhancement issue.

Additional context

If there's a preferred way of accomplishing my goal without this change, I'm all ears!

Fixes: #123

[weissleb]

@ndom91 just nudging here. It looks like you're still maintaining this package. I realize you may be quite busy, but hoping it is reasonable to get this merged, or commented on, so we can start using this in production without our fork. Very much appreciated.

[ndom91]

Hey thanks for the reminder 😅 . This looks like a sane, small, change.

Thanks!