put https://{environment}.masspay.io/{VERSION}/attribute/label///
This PUT endpoint sets or updates a human-readable label for a given attr_set_token. Labels help identify the context of the attribute set — for example, assigning a label like "JPMorgan Chase" to represent attributes linked to that specific destination or financial institution. Provide the attr_set_token as a path parameter and the desired label in the request body. If a label already exists for the attribute set, it will be overwritten.