initializing maps

provider/helm/common.go

@@ -43,6 +43,7 @@ func getImages(vals chartutil.Values) ([]*types.TrackedImage, error) {
 			Image:                imageRef,
 			PollSchedule:         keelCfg.PollSchedule,
 			Trigger:              keelCfg.Trigger,
+			SemverPreReleaseTags: make(map[string]string),
 		}
 
 		images = append(images, trackedImage)

provider/kubernetes/kubernetes.go

@@ -178,6 +178,7 @@ func (p *Provider) TrackedImages() ([]*types.TrackedImage, error) {
 				Namespace:            gr.Namespace,
 				Secrets:              secrets,
 				Meta:                 make(map[string]string),
+				SemverPreReleaseTags: make(map[string]string),
 			})
 		}
 	}