Refactor wallabag stack name and repo variables

Brought in line with other stack naming schemes.

roles/wallabag/handlers/main.yml

@@ -15,28 +15,28 @@
   listen: "update wallabag upstream"
 
 # figure out if upstream id exists
-- name: check {{ stack.name }} upstream
+- name: check {{ stack_name }} upstream
   community.docker.docker_container_exec:
     container: "{{ caddy_container_id }}"
     command: >
-      curl localhost:2019/id/{{ stack.name }}_upstream/
+      curl localhost:2019/id/{{ stack_name }}_upstream/
   changed_when: False
   register: result
   become: true
   listen: "update wallabag upstream"
 
 # upstream already exists, patch it
-- name: remove old {{ stack.name }} upstream
+- name: remove old {{ stack_name }} upstream
   community.docker.docker_container_exec:
     container: "{{ caddy_container_id }}"
     command: >
-      curl -X DELETE localhost:2019/id/{{ stack.name }}_upstream/
+      curl -X DELETE localhost:2019/id/{{ stack_name }}_upstream/
   become: true
   when: (result.stdout | from_json)['error'] is not defined
   listen: "update wallabag upstream"
 
 # upstream has to be created
-- name: add {{ stack.name }} upstream
+- name: add {{ stack_name }} upstream
   community.docker.docker_container_exec:
     container: "{{ caddy_container_id }}"
     command: >
@@ -50,4 +50,3 @@
     state: absent
   become: true
   listen: "update wallabag upstream"
-