mkosi: Enable KVM

Since https://github.blog/2024-01-17-github-hosted-runners-double-the-power-for-open-source/,
it seems that KVM is supported on GA runners, so let's explicitly
enable it to make sure it is used.

We update mkosi to latest and set QemuFirmware=uefi to disable
secure boot which crashes qemu until https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2038777
is fixed.

.github/workflows/mkosi.yml

@@ -76,7 +76,7 @@ jobs:
 
     steps:
     - uses: actions/checkout@9bb56186c3b09b4f86b1c65136769dd318469633
-    - uses: systemd/mkosi@ea1b00c3dba12662214b2e95dd1fe837cb13664b
+    - uses: systemd/mkosi@1445b389750af22756c0fde6facc1f2f343340b4
 
     - name: Free disk space
       run: |
@@ -99,7 +99,9 @@ jobs:
         ToolsTreeDistribution=fedora
         QemuVsock=yes
         # Sometimes we run on a host with /dev/kvm, but it is broken, so explicitly disable it
-        QemuKvm=no
+        QemuKvm=yes
+        # TODO: Drop once https://bugs.launchpad.net/ubuntu/+source/linux/+bug/2038777 is fixed in Github Actions
+        QemuFirmware=uefi
         Ephemeral=yes
         EOF