Reverting d477018b57 "gnu: poetry: Update to 1.1.12."

[Tanguy LE CARROUR]

Hi Guix,

I noticed yesterday that Poetry was broken:
<https://ci.guix.gnu.org/build/1227911/details>.

I might have spotted it earlier if I had spend time testing `core-update`.
My bad!

The problematic commit seems to be d477018b57 "gnu: poetry: Update to 1.1.12.".

What also questions me is the fact that the commit message states that
it's an upgrade to `1.1.12` when it's the current version and it's
actually an upgrade to `1.4.2`.

Unfortunately, I have no time to work on this right now. Would it be
possible to revert the change? Or should I submit a patch to downgrade it?

Cheers,

-- 
Tanguy