pve-headers-$(uname -r) is equivalent to
linux-headers-$(uname -r)-amd64
pve-kernel-$(uname -r) is equivalent to
linux-image-$(uname -r)-amd64
By adding a provides this should help users running
`apt install linux-headers-$(uname -r)-amd64` which is commonly
suggested in install instructions for third-party kernel-drivers on
plain debian.
Signed-off-by: Stoiko Ivanov <s.ivanov@proxmox.com>