Release ISOs are not valid more than a day.

Hi,

thanks for picking up the slack after covertsh/ubuntu-autoinstall-generator died.

My issue: Even if I choose to download a release, -r it will be kept with a filename including the download data and will not be picked up the following day.

I have some ready, wait for it.

[cloudymax]

thanks for finding this 🙏

@cloudymax thanks for picking up the slack on the autoinstaller.