fix linting issues

pkg/registry/auth/auth.go

@@ -150,6 +150,7 @@ func GetAuthURL(challenge string, img string) (*url.URL, error) {
 	return authURL, nil
 }
 
+// GetScopeFromImageName normalizes an image name for use as scope during auth and head requests
 func GetScopeFromImageName(img, svc string) string {
 	parts := strings.Split(img, "/")
 	scopeImage := ""