Define schema for drush alias uris

templates/drush-9.site.yml.jinja2

 {% for domain in drupal.domains %}
 {{ domain.shortname|default("default") }}:
   root: {{ webRoot }}{{ drupal.root|default("") }}/
-  uri: {{ domain.domain }}
+  uri: {{ domain.protocol|default("https") }}://{{ domain.domain }}
 {% endfor %}