updated the virtual server

The virtual server that runs my stuff was on 2020-era Debian Stretch LTS. There were reports it was ok to go Stretch->Bullseye but I was skeered.

I went Stretch->Buster->Bullseye and nothing major broke.

1. edit /etc/apt/sources.list for the new target
2. apt update
3. apt upgrade
4. apt full-upgrade
5. apt autoremove
6. syscontrol reboot
7. repeat

The only thing (I know of) that broke was my blogging software; it had ruby2.3 hardcoded in the shebang and I changed that to just ruby since we are now on 2.7

Updated to add:

• rsync was gone for some reason. Reinstalled with apt install rsync
• youtube-dl was broken, or even more broken. Already jumped ship to the superior and actively-developed yt-dlp so I deleted the former.