[Merge] lp:~xnox/ubuntu-archive-publishing/migrate-dist-upgrade-to-4k into lp:ubuntu-archive-publishing

[Adam Conrad]

> I'm not sure which is the more obvious place for us to enforce this.

I think the more transparent place to enforce it is in the code.  Maybe the keys in the keyring should have better defaults, but if we want a specific digest, we should be explicit about that in the code, not implicitly hope that the keyring has it set how we want (even if/when it does).
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https://code.launchpad.net/~xnox/ubuntu-archive-publishing/migrate-dist-upgrade-to-4k/+merge/311181
Your team Ubuntu Package Archive Administrators is requested to review the proposed merge of lp:~xnox/ubuntu-archive-publishing/migrate-dist-upgrade-to-4k into lp:ubuntu-archive-publishing.