Add 3.7 schema and add rollback_config to it

[vdemeester]

Mirrors docker/cli#409. As for update_config, it will be ignore by docker-compose 😉

cc @thaJeztah@shin-

[thaJeztah]

18.06.0?

[vdemeester]

well, I wasn't sure about that. From my understanding, it's the "lowest" API version supported. And so far, there is nothing in v3.7 that wasn't already supported by v3.6 ; this is why I did put the same version.

[shin-]

It's true that we used to do that, however, in retrospect it confuses people and makes things harder to document. For people who insist on using newer Compose file versions with an older engine (I don't think there are many), they can always set COMPOSE_API_VERSION to override.

As a result I'd recommend using 18.06.0 here.

[shin-]

LGTM other than that one thing

[vdemeester]

Updated 👼

[shin-]

Thank you! 🥇

[thaJeztah]

Note that ideally, we'd have some other compose-file changes in as well;

• Add --init option to docker service create cli#479 - but haven't found the time yet to carry that; I tried, but ran into some issues
• Add --template-driver option for secrets/configs cli#896 - templating driver option

@shin- not sure if you work with release-branches, so let me know if you were planning to do a release (because after it's in a release, we likely can't change the compose-file spec anymore)

@vdemeester for the above; issues; I'll try to find some time, but if you have some and can help 🤗

[shin-]

@thaJeztah I don't think we'll do a release before at least mid-June, so things should be alright on that end.

[thaJeztah]

Thanks! Feel free to ping me if things change in that respect 👍

[vdemeester]

@thaJeztah can take care of it 😉

[thaJeztah]

@vdemeesterdocker/cli#479 could be tricky; when I had the CLI working, I think SwarmKit still didn't pick up the configuration (but perhaps I did something wrong); I can push that branch as a quick WIP