Revert "Drop the APT GPG key from images that get it via the base container"

This reverts commit 7d4bce20. This
change introduces using a keyring from the system path, which requires
features which are not (yet) in our packaged version of debos.

This feature is introduced in debos commit d2ab9d3b08056c416bfbcd63c01199e14b2fc3b9

Signed-off-by: Christopher Obbard <chris.obbard@collabora.com>

image-builder/test-recipe.yaml

@@ -12,6 +12,6 @@ actions:
       - target
     mirror: {{ $mirror }}
     variant: minbase
-    keyring-package: {{ $osname }}-archive-keyring
-    keyring-file: /etc/apt/trusted.gpg.d/{{ $osname }}-archive-keyring.gpg
+    keyring-package: apertis-archive-keyring
+    keyring-file: keyring/apertis-archive-keyring.gpg
     merged-usr: true