Upsert Category Trees

Upserts category trees. This single endpoint updates and creates category trees. If a tree object contains an ID, it is processed as an update operation using that ID. If you do not provide an ID, a new tree is created. The category tree `name` field is required to create trees, but is not required on the update. **Usage Notes** * Channel ID in the `channels` field is required to create a category tree. You can only assign a category tree to one channel. * The `channels` field must be absent when updating a category tree. This field is currently unsupported during a category tree update.