release: add the public key for the signed drivers

The public key can be used by users to enable the secure boot.
For the technical detail about the secure boot and driver signing,
please see
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/managing_monitoring_and_updating_the_kernel/signing-a-kernel-and-modules-for-secure-boot_managing-monitoring-and-updating-the-kernel

Signed-off-by: Manish Regmi <manish.regmi@intel.com>

Author: mregmi