when multiple kernels and initrds exist, use the latest

[edgood1]

When multiple kernels or initrds exist the process fails with the error

Step 7/8 : RUN mv $(find /boot -name 'vmlinuz-*') /boot/vmlinuz &&       mv $(find /boot -name 'initrd.img-*') /boot/initrd.img
 ---> Running in 6de2cb0b8003
mv: target '/boot/initrd.img' is not a directory

This is a quick fix to take the latest of each.

[Adphi]

Hi @edgood1, thanks for your pull request 😀
Can you please squash the commits and [sign] (https://docs.github.com/en/authentication/managing-commit-signature-verification/signing-commits) ?

[Adphi]

Thanks !