[tz] Update Ukrainian Timezones Names

Hi, maintainers of tz, This file was requested by [eggert](https://github.com/eggert/tz/pull/26#issuecomment-595995177). I hope you apply this patch, cause those fantasy names you have on the project now are a real confusion for Ukrainians who are probably 99% of users of Ukrainian timezones. My initial comment: Default timezone names for Ukraine, e.g. Europe/Kiev, are more understandable and correct than ridiculous fantasy style, e.g. Ruthenia. Previous names cause confusion, misunderstanding and are considered inappropriate. Proofs: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=198822, https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=47468, https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=244644. Thanks!