Add default arch

Author: MaxBed4d

roles/os_images/tasks/images.yml

@@ -85,7 +85,7 @@
     dib_args: >-
       {% if item.size is defined %}--image-size {{ item.size }}{% endif %} {% if item.type is defined %}-t {{ item.type }}{% endif %}
       {% if item.packages | default %}-p {{ item.packages | join(',') }}{% endif %} {{ os_images_common }} {{ item.elements | join(' ') }}
-      -o {{ item.name }} -a {{ os_images_architecture }}
+      -o {{ item.name }} -a {{ os_images_architecture | default('amd64') }}
   ansible.builtin.shell: . {{ os_images_dib_venv }}/bin/activate && disk-image-create {{ dib_args }} > {{ item.name }}.stdout 2> {{ item.name }}.stderr
   args:
     chdir: "{{ os_images_cache }}/{{ item.name }}"