Update a channel's settings. Requires the MANAGE_CHANNELS permission for the guild. Returns a channel on success, and a 400 BAD REQUEST on invalid parameters. Fires a Channel Update Gateway event. If modifying a category, individual Channel Update events will fire for each child channel that also changes. If modifying permission overwrites, the MANAGE_ROLES permission is required. Only permissions your bot has in the guild or channel can be allowed/denied (unless your bot has a MANAGE_ROLES overwrite in the channel). All JSON parameters are optional.