New "DIV.ROC" option corporate action activity sub-type

Broker API

Adds DIV.ROC (Return of Capital) to the option corporate action (OPCA) values of the ActivitySubType schema, so return-of-capital events on option positions are reported with their own sub-type.

• The OPCA sub-type mapping in activity_sub_type now documents DIV.ROC.
• The options cash dividend activity schema now covers cash dividend and return of capital events.

Affected Endpoints

• GET /v1/accounts/activities
• GET /v1/accounts/activities/{activity_type}
• GET /v2beta1/accounts/{account_id}/events/activities/{event_id}
• GET /v2beta1/events/activities