Add --dry-run option to pull cmd

[satotake]

What I did

Add --dry-run option to pull command. Our final goal is adding the --dry-run to up and I started with the case of pull at first. This is a proposal.

Example usage

$ docker compose --project-directory local/e2e/compose/fixtures/dry-run-test/pull/ pull  --dry-run
SERVICE             IMAGE                           PLAN                REMOTE DIGEST
expectedFetch       hello-world                     fetch               sha256:9f6ad537c5132bcce57f7a0a20e317228d382c3cd61edae14650eec68b2b345c
expectedSkip        alpine                          skip                sha256:234cb88d3020898631af0ccbbcca9a66ae7306ecd30c9720690858c1b007d2a0
expectedFail        expected-not-to-be-registered   fail                <none>

$ docker compose --project-directory local/e2e/compose/fixtures/dry-run-test/pull/ pull  --dry-run --format json
{
    "Services": [
        {
            "Name": "expectedSkip",
            "Image": "alpine",
            "LocalDigests": [
                "sha256:234cb88d3020898631af0ccbbcca9a66ae7306ecd30c9720690858c1b007d2a0"
            ],
            "DistributionDigest": "sha256:234cb88d3020898631af0ccbbcca9a66ae7306ecd30c9720690858c1b007d2a0",
            "Plan": "skip"
        },
        {
            "Name": "expectedFail",
            "Image": "expected-not-to-be-registered",
            "LocalDigests": [],
            "DistributionDigest": "",
            "Plan": "fail"
        },
        {
            "Name": "expectedFetch",
            "Image": "hello-world",
            "LocalDigests": [],
            "DistributionDigest": "sha256:9f6ad537c5132bcce57f7a0a20e317228d382c3cd61edae14650eec68b2b345c",
            "Plan": "fetch"
        }
    ]
}

Related issue https://github.com/docker/compose-cli/issues/1090

UPDATE: Example usages' style was broken. fixed.

[satotake]

First-time contributors need a maintainer to approve running workflows.

Hi maintainers. Could you run workflows again?