fix: consumer-group scoped plugins not showing tags

On running deck file render command, tags were
coming up for global and service/route scoped
plugins. However, for consumer-group scoped
plugins, the tags did not populate. This was because
the underlying struct did not have tags in the first
place.

This change updates the underlying struct for
consumer-group plugins by adding tags to them
as well. This will ensure that tags show up
during deck file render.
For: Kong/deck#1417

kong/consumer_group.go

@@ -42,6 +42,7 @@ type ConsumerGroupPlugin struct {
 	Config        Configuration  `json:"config,omitempty" yaml:"config,omitempty"`
 	ConsumerGroup *ConsumerGroup `json:"consumer_group,omitempty" yaml:"consumer_group,omitempty"`
 	ConfigSource  *string        `json:"_config,omitempty" yaml:"_config,omitempty"`
+	Tags          []*string      `json:"tags,omitempty" yaml:"tags,omitempty"`
 }
 
 // FriendlyName returns the endpoint key name or ID.