migrations: archive previous releases

[bcressey]

Issue number:
Previously: #3633, #2800, #2606, ...

Description of changes:
This avoids rebuilding existing migrations and reduces build times.

Testing done:
Builds work.

Terms of contribution:

By submitting this pull request, I agree that this contribution is dual-licensed under the terms of both the Apache License, version 2.0, and the MIT license.

[webern]

Are there consequences to upgrade/downgrade workflows of archiving, e.g. 1.20 so soon?

[bcressey]

Are there consequences to upgrade/downgrade workflows of archiving, e.g. 1.20 so soon?

Not necessarily but it depends on how the upgrade/downgrade workflow is handled.

As I understand it, the problem is with a sequence like this:

build old version
build new version
sync repo

The old version will create a migrations RPM during os build with all the older migration binaries. However, if that's not synced up to the repo, then when the new version is built, a new migrations RPM will be created with only the subset of current migration binaries.

I expect a sequence like this would be fine:

build old version
sync repo
build new version
sync repo