Add task groups to the Plugin API

[dralley]

Somehow this never got added to the plugin API even though I remember making the change, it must have gotten accidentally stashed or something. There's already a changelog entry... we can send this out in a Y release.

re: #6414
https://pulp.plan.io/issues/6414

[pulpbot]

Warning: Issue #6414 is not at NEW/ASSIGNED/POST.

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[daviddavis]

I thought this over and I think we need a new issue that we can add to a 3.3.1 milestone plus changelog entry that will show up in the 3.3.1 changelog.

[dralley]

The changelog entry that already went out in 3.3.0 already mentions "plugin writers", so it arguably doesn't need a changelog entry. wdyt?

Here's what it says:

Task Groups added -- Plugin writers can spawn tasks as part of a "task group", which facilitates easier monitoring of related tasks

[daviddavis]

If #6414 were unreleased (and at MODIFIED) then I think it would be ok. My understanding of our release process though is that we can't/shouldn't attach changes to released issues.

[bmbouter]

If #6414 were unreleased (and at MODIFIED) then I think it would be ok. My understanding of our release process though is that we can't/shouldn't attach changes to released issues.

This is also my understanding. An issue can't be fixed in two releases. Additionally it creates issues for any downstream during their cherry picking process.