Reorganize the "list tags failed" logic in inspect.go a bit

... to allow adding more cases.

Signed-off-by: Miloslav Trmač <mitr@redhat.com>

cmd/skopeo/inspect.go

@@ -205,9 +205,13 @@ func (opts *inspectOptions) run(args []string, stdout io.Writer) (retErr error)
 		if err != nil {
 			// Some registries may decide to block the "list all tags" endpoint;
 			// gracefully allow the inspect to continue in this case:
+			fatalFailure := true
 			// - AWS ECR rejects it with 403 (Forbidden) if the "ecr:ListImages"
 			//   action is not allowed.
-			if !strings.Contains(err.Error(), "403") {
+			if strings.Contains(err.Error(), "403") {
+				fatalFailure = false
+			}
+			if fatalFailure {
 				return fmt.Errorf("Error determining repository tags: %w", err)
 			}
 			logrus.Warnf("Registry disallows tag list retrieval; skipping")