v3.2.0

Carry Cardmarket's signed, altered and graded flags (#7)

* Carry Cardmarket's signed, altered and graded flags

The API returns these per-listing attributes now. An offer carrying any
of them is real and is returned, but it does not contribute to the card's
market price, which means the cheapest row the SDK hands back is not
necessarily the card's market_price. That is easy to get wrong and was a
live pricing bug before the pipeline learned to tell these apart, so the
README states it outright and shows the filter.

* chore: release v3.2.0