Upgrade to Borg 2 and Borgmatic 2

[benoit74]

See https://torsion.org/borgmatic/how-to/upgrade/#upgrading-borg

I'm not sure if we use Borg 1 or Borg 2 repos, but since we use borgmatic 1.5.24 we probably still use Borg1

And Borg2 does not seem ready for production : https://github.com/borgbackup/borg

Not sure we should move forward for now.

[rgaudin]

What should be discussed in this repo? I believe we only use it via bord-backup, right?

[benoit74]

I've made the issue here, because we probably need to make (manual?) changes to borgbase repos as well at some point, not sure only updating borg-backup image is sufficient. But it is indeed somewhere between these two repos. (and it is somehow a trick, I'm quite sure opening the issue in borg-backup the issue would never make any progress / I would not find it again in 2 months from now)