Merge ~xnox/maas-images:amd64-uefi-focal into maas-images:master

[Dimitri John Ledkov]

We should bump all bootloaders to focal.

However, lets start with amd64 EFI as that upgrades grub from 2.02 to 2.04 which has fixes for TPM measured boot.

I have tested the 2.04 grub by sideloading it, with/without secureboot on ps5 nodes. Deployed Ubuntu and Centos. But not sure what further testing should be done.

[Julian Andres Klode (juliank)]

Sounds good to me, I mean we've already tested grub 2.04 in a lot of other ways already given that it's been released for almost a year now.

review: Approve

diff --git a/conf/bootloaders.yaml b/conf/bootloaders.yaml
index 7fd275e..43e6434 100644
--- a/conf/bootloaders.yaml
+++ b/conf/bootloaders.yaml
@@ -22,7 +22,7 @@ bootloaders:
    arch: amd64
    arches: amd64
    archive: http://archive.ubuntu.com/ubuntu
-   release: bionic
+   release: focal
    os: grub-efi-signed
    files:
     - usr/lib/shim/shimx64.efi.signed, bootx64.efi