Changes to Retrieve workflow activity

the response property action became required for the status 200

the response property annotation became required for the status 200

the response property assignees became required for the status 200

the response property created_at became required for the status 200

the response property created_by became required for the status 200

the response property id became required for the status 200

the response property note became required for the status 200

the response property organization became required for the status 200

the response property url became required for the status 200

the response property workflow became required for the status 200

the response property workflow_run became required for the status 200

the response property workflow_step became required for the status 200