Actualización Proxmox 6.x --> 7.x

https://forum.proxmox.com/threads/you-are-attempting-to-remove-the-meta-package-proxmox-ve.111616/#post-482257
rm -rf /var/lib/apt/lists/*
apt update

----------

https://forum.proxmox.com/threads/after-migration-6-7-you-are-attempting-to-remove-the-meta-package-proxmox-ve.96754/
echo "deb http://download.proxmox.com/debian/ceph-octopus bullseye main" > /etc/apt/sources.list.d/ceph.list