add ctr pull metadata-only

[ningmingxiao]

No description provided.

[k8s-ci-robot]

Hi @ningmingxiao. Thanks for your PR.

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[ningmingxiao]

https://github.com/containerd/containerd/blob/main/cmd/ctr/commands/images/pull.go#L126 this line is useless before my commit.

[mxpv]

Trying to understand this if statement:

if context.Bool("metadata-only") {
  sopts = append(sopts, image.WithAllMetadata)
} else if !context.Bool("skip-metadata") {
  sopts = append(sopts, image.WithAllMetadata)
}

we don't need both flags, right?
we include all metadata by default unless skip-metadata specified.

[ningmingxiao]

Trying to understand this if statement:

if context.Bool("metadata-only") {
  sopts = append(sopts, image.WithAllMetadata)
} else if !context.Bool("skip-metadata") {
  sopts = append(sopts, image.WithAllMetadata)
}

we don't need both flags, right? we include all metadata by default unless skip-metadata specified.

done

[ningmingxiao]

already rebase