Merchant card product category renamed

When calling the list products or retrieve product endpoints, the category name of merchant cards has changed. We previously returned the plural merchant_cards even though our documentation specified the singular merchant_card.

We made this change to align our API responses with our documentation. Unfortunately, we did not at the time realize that this was a breaking change for some existing integrations. We thus failed to communicate this change proactively. We are very sorry for this omission.

This change was rolled out on January 18th. This changelog was published on March 6th.