Change become arguments to boolean

Changed all 'become: ' values from 'yes' to 'true' to satisfy the schema
(and also make the lsp shut up).

roles/miniflux/tasks/main.yml

@@ -7,7 +7,7 @@
       curl localhost:2019/id/{{ stack_name }}_upstream/
   register: result
   changed_when: (result.stdout | from_json) != (lookup('template', 'upstream.json.j2') | from_yaml)
-  become: yes
+  become: true
   notify: "update miniflux upstream"
 
 - name: Deploy miniflux to swarm
@@ -17,7 +17,7 @@
     prune: yes
     compose:
       - "{{ stack_compose }}"
-  become: yes
+  become: true
   tags:
     - docker-swarm
   notify: "update miniflux upstream"