Bug#696185:

[Akbarkhon Variskhanov <akbarkhon.variskhanov@gmail.com>]

FSF[1] as well as SPDX[2] request using the suffixes "-only" or
"-or-later" with GNU licenses:

> Therefore, when you use SPDX license indicators, please use these:
> GPL-2.0-only or GPL-2.0-or-later

DEP-5 uses the bare form, i.e. "GPL-3" or "GPL-3+". I added this
difference to the wiki page.

What's not clear is how are we going to approach this discrepancy?
Shall we a) ignore this, b) adopt SPDX/FSF naming, or c) suggest SPDX
to stick to uniform naming convention, which is using "+" to denote
later versions of a license?

[1] https://www.gnu.org/licenses/identify-licenses-clearly.html
[2] https://spdx.dev/ids/