Update the update_molecule_images.sh helper script

Adjust the script to pull down platform specific images instead of just
the image of the running system's platform. This will ensure that all
images needed by the molecule configuration are retrieved regardless of
the system platform.

update_molecule_images.sh

@@ -45,4 +45,4 @@ check_dependencies
 # Note that we can't use --max-args in place of -n in the xargs
 # command since the version of xargs distributed with macOS does not
 # support it.
-yq '.platforms[].image' < "$source_file" | xargs -n 1 docker pull
+yq '.platforms[] | "\(.platform) \(.image)"' < "$source_file" | xargs -n 2 docker pull --platform