Track released version

[adiroiban]

We need some way to make it easy to see in which version a ticket or a PR was released/included.

I prefer not to use tags for this, to reduce polluting the list of tags.

In an ideal world, we will use "projects" , but maybe it's easier to use milestones.

For example, once a ticket or PR is closed it is automatically associated with the milestone "current-release" or "ongoing-release" or "wip-release"

The problems is that milestones are per-repo.
So maybe as a start, it's OK to enable this only for chevah/server generated events.

This is all that the hook server should do.

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Once the release is done, we can manually move all the ticket from "current-release" milestone to a release specific milestone like "version-3.15.0"

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To help the support team is important that when we see a ticket or PR in github we can get a quick info for when this change was made available to end users.

We still have the release notes, and you can search for ticket ID inside the release note.
But this required extra context switch .