[PATCH] Add COPYINGv3 with the GPL version 3 text

[Florian Weimer]

* Paul Eggert:

> On 2025-11-11 03:15, Florian Weimer wrote:
>> The license is referenced in various headers, so we should ship it.
>
> Agreed, but the resulting names are a bit confusing, as COPYING is v2
> but its name does not say "v2".
>
> Also, the existing COPYING and COPYING.LIB files have out-of-date
> contents (they contain US mail addresses that are no longer valid).
>
> So I suggest copying Gnulib's COPYINGv2, COPYINGv3 and
> COPYING.LESSERv2 files verbatim, with the same names as Gnulib, and
> removing the old COPYING and COPYING.LIB files.

COPYING.LIB is widely referenced in copyright notices.  In general, I
don't want to change copyright notices.

Thanks,
Florian