[tz] IANA timezone database - request to add Omaha, Nebraska

[Steve Summit]

Guy Harris wrote:
> From some quick tests on my collection of macOS VMs, the change from
> links to copies appears to have occurred in High Sierra.  I have some
> vague memory of this having been brought up on the list at some point.

I believe Deborah mentioned it had to do with tz files being
distributed by an "over the air" mechanism which does not know
how to handle links.

https://mm.icann.org/pipermail/tz/2021-February/029825.html
https://mm.icann.org/pipermail/tz/2021-February/029836.html