Add experimental --upgrade flag to update-service

- allows for upgrade of an individual service instance to the latest maintenance_info version on the plan

[#164496184]

Co-authored-by: Oleksii Fedorov <ofedorov@pivotal.io>
Co-authored-by: George Blue <gblue@pivotal.io>
Co-authored-by: Aarti Kriplani <akriplani@pivotal.io>

actor/v2action/actor.go

@@ -1,4 +1,5 @@
-// Package v2action contains the business logic for the commands/v2 package
+// Package v2action contains the business logic for the commands/v6 package
+// Actors in this package should only call CC v2 API endpoints
 package v2action
 
 // Warnings is a list of warnings returned back from the cloud controller

actor/v2action/cloud_controller_client.go

@@ -92,6 +92,7 @@ type CloudControllerClient interface {
 	UpdateRouteApplication(routeGUID string, appGUID string) (ccv2.Route, ccv2.Warnings, error)
 	UpdateSecurityGroupSpace(securityGroupGUID string, spaceGUID string) (ccv2.Warnings, error)
 	UpdateSecurityGroupStagingSpace(securityGroupGUID string, spaceGUID string) (ccv2.Warnings, error)
+	UpdateServiceInstanceMaintenanceInfo(serviceInstanceGUID string, maintenanceInfo ccv2.MaintenanceInfo) (ccv2.Warnings, error)
 	UpdateServicePlan(guid string, public bool) (ccv2.Warnings, error)
 	UpdateSpaceDeveloper(spaceGUID string, uaaID string) (ccv2.Warnings, error)
 	UpdateSpaceDeveloperByUsername(spaceGUID string, username string) (ccv2.Warnings, error)