Make backup script use two character numbers for file naming

Improvements
1

The current backup process: “sudo /root/mailinabox/management/backup.py --full”
understandably creates many volumes but uses a single digit for the first 9 volumes and then goes to two digits. I am proposing that it uses two, maybe even three, digits from the onset so that the files automatically sort correctly.

I am seeking to avoid this;
duplicity-full.20260208T080248Z.vol19.difftar.gpg
duplicity-full.20260208T080248Z.vol1.difftar.gpg
duplicity-full.20260208T080248Z.vol20.difftar.gpg

would expect to see;
duplicity-full.20260208T080248Z.vol01.difftar.gpg
…02 through 18 in between…
duplicity-full.20260208T080248Z.vol19.difftar.gpg
duplicity-full.20260208T080248Z.vol20.difftar.gpg

Thanks for hearing me out.
Keith.

2

Now that I watching paint dry while the full backup runs, I am wondering if the request should be filed with Duplicity authors instead of MiaB.

3

Still watching paint dry…
Use four digits from the start is probably more prudent. I exceeding 100 volumes and now they are poorly sorted even more.