Remove warn parameter for ansible>=2.14 (#286)

Author: Matt Pryor

ansible/roles/grafana-dashboards/tasks/main.yml

@@ -39,7 +39,6 @@
         -o {{ _tmp_dashboards.path }}/{{ item.dashboard_id }}.json
       args:
         creates: "{{ _tmp_dashboards.path }}/{{ item.dashboard_id }}.json"
-        warn: false
       register: _download_dashboards
       until: _download_dashboards is succeeded
       retries: 5