set filename for docker repo

roles/docker/tasks/docker.yml

@@ -33,6 +33,7 @@
 - name: add docker repo
   become: true
   ansible.builtin.apt_repository:
+    filename: docker
     repo: "deb [arch={{ docker_arch.stdout }}] https://download.docker.com/linux/debian {{ ansible_distribution_release }} stable"
     state: present
     update_cache: true