create tasks for cron extension

roles/common/tasks/postgres_cron.yml

@@ -55,8 +55,8 @@
     - timescaledb_install
   postgresql_query:
     db: "{{ timescaledb_database_name }}"
-    login_user: "{{ timescaledb_database_user }}"
-    login_password: "{{ timescaledb_database_password }}"
+    login_user: "{{ postgres }}"
+    login_password: "{{ postgresql_admin_password }}"
     login_host: "{{ lxc_ip }}"
     query:
       - CREATE EXTENSION pg_cron;