Code review comment for ~alexmurray/ubuntu-qa-tools:unembargo-warn-security-updates-on-fridays

This looks good to me, approving.

Extremely minor nits that absolutely do not block merging would be:

- use of magic numbers; it'd be nice not to have to remember that 4 == friday; not sure if the python libraries have a constant defined for this.

- a lot of our scripts do a lot o stuff inline, resuliting in long code sequences that an be overwhelming. This makes things slightly harder to understand and harder to write unit tests for. I don't necessarily think this added check is worth bothering with a separate function (expecially because most of the added bits is handling what to do if the check trips), but it's worth thinking about as we add things.

- if you're going to rebase or add commits after you've gone ahead and made a merge request, it's nice to add a reference link to the merge request in your commit message.

Thanks for the nice improvement!