oras push/cp --digest-only

[SteveLasker]

To support tag update scenarios, where a new digest, and all its references should be pushed before a tag update is applied, we need a way to push a container image, or any artifactType, deferring the tag application.

Initially, I considered docker push --digest-only, and that may still be the best idea. Except, that would require a change to the docker client.
This proposal focuses on oras push with a --digest-only flag.

Perhaps oras cp with --digest-only

See Docs: Add Promoting Scenario oras-project/oras#98 for more info

[sajayantony]

@SteveLasker - Looks like you moved this back to the wrong repo. This is a CLI experience feature request and not a library issue. Please close this or transfer it to the CLI repo.

[shizhMSFT]

oras push without a tag means "pushing with digest only".

[SteveLasker]

@shizhMSFT, correct.

[qweeah]

@JunczhuMSFT this is related to the copy command, can you take a look?

[shizhMSFT]

Closed by notaryproject/notation#432