Update an existing Collection.

Update the details of an existing Collection using a specific ID. Using this API call you can update the collection's identifier, status, contents, and the leaderboards. You can also add new contents and assign other leaderboards to the collection. Learner Leaderboards could not be updated directly using this API. The Collection ID is required for this API call. Collection ID's can be found by using the List Collections (/collection) API call.