Upstream branches are no longer updated automatically

[davidmhewitt]

We removed the deploy key that was automatically pushing stuff to the unpatched upstream package branches. This means any upstream Ubuntu package updates will not automatically make their way down to the os-patches PPA.

The packages in that PPA are built by merging the -patched branch on top of the unpatched branch, so the rebasing and updating of the -patched branch doesn't matter so much, just that the unpatched branch is up to date with upstraem.

In the short-term, we'll need to update these branches manually. We'll get issue reports from the daily CI workflow telling us a package is out of date.

In the long term, it'll probably be best to have the CI workflow automatically update those branches.