autopkgtest fails 'rebuild' test due to missing/deleted spl-linux version in debian/dkms-versions

The autopkgtests for the bionic linux-aws-edge kernel have recently started failing:
http://autopkgtest.ubuntu.com/packages/l/linux-aws-edge/bionic/amd64

this is because their debian/dkms-versions contains:
spl-linux 0.7.12-1ubuntu3
zfs-linux 0.7.12-1ubuntu5.1
nvidia-graphics-drivers-390 390.116-0ubuntu1
nvidia-graphics-drivers-418 418.56-0ubuntu1

however that version of spl-linux is from disco, and it was recently removed from the archives, resulting in the 'rebuild' test failing because it can't download that version of the spl-dkms package. Note that none of those dkms versions are still available in the archives.

The debian/dkms-versions file should be updated to use a newer versions that are still present in the archives.