fix: teach app version command to read new versions

pkg/client/stack/stack.go

@@ -93,6 +93,19 @@ func GetAllDeployedServices(contextName string) StackStatus {
 	return StackStatus{services, nil}
 }
 
+// GetDeployedServicesByName filters services by name
+func GetDeployedServicesByName(ctx context.Context, cl *dockerclient.Client, stackName, serviceName string) StackStatus {
+	filters := filters.NewArgs()
+	filters.Add("name", fmt.Sprintf("%s_%s", stackName, serviceName))
+
+	services, err := cl.ServiceList(ctx, types.ServiceListOptions{Filters: filters})
+	if err != nil {
+		return StackStatus{[]swarm.Service{}, err}
+	}
+
+	return StackStatus{services, nil}
+}
+
 // IsDeployed chekcks whether an appp is deployed or not.
 func IsDeployed(ctx context.Context, cl *dockerclient.Client, stackName string) (bool, string, error) {
 	version := ""