Update docker.io/pretix/standalone Docker tag to v2026.4

With time the volume seems to just keeps growing with cache data, so
clean it up once a day.

resources/chaosknoten/tickets/docker_compose/compose.yaml.j2

@@ -25,7 +25,7 @@ services:
       backend:
 
   pretix:
-    image: docker.io/pretix/standalone:2026.3
+    image: docker.io/pretix/standalone:2026.4
     command: ["all"]
     ports:
       - "8345:80"

roles/renovate/files/renovate-cleanup.service

@@ -0,0 +1,7 @@
+[Unit]
+Description=renovate cleanup (delete docker volume)
+Conflicts=renovate.service
+
+[Service]
+Type=oneshot
+ExecStart=/usr/bin/docker volume rm renovate

roles/renovate/files/renovate-cleanup.timer

@@ -0,0 +1,9 @@
+[Unit]
+Description=renovate cleanup (delete docker volume) running daily
+
+[Timer]
+# @daily with 10 minute offset
+OnCalendar=*-*-* 00:10
+
+[Install]
+WantedBy=timers.target

roles/renovate/tasks/main.yaml

@@ -16,31 +16,28 @@
     mode: "0640"
   become: true
 
-- name: ensure systemd service exists
+- name: ensure systemd services and timers exist
   ansible.builtin.copy:
-    src: renovate.service
-    dest: /etc/systemd/system/renovate.service
+    src: "{{ item }}"
+    dest: "/etc/systemd/system/{{ item }}"
     owner: root
     group: root
     mode: "0644"
   become: true
+  loop:
+    - renovate.service
+    - renovate-cleanup.service
+    - renovate.timer
+    - renovate-cleanup.timer
   notify:
     - systemd daemon reload
 
-- name: ensure systemd timer exists
-  ansible.builtin.copy:
-    src: renovate.timer
-    dest: /etc/systemd/system/renovate.timer
-    owner: root
-    group: root
-    mode: "0644"
-  become: true
-  notify:
-    - systemd daemon reload
-
-- name: ensure systemd timer is started and enabled
+- name: ensure systemd timers are started and enabled
   ansible.builtin.systemd_service:
-    name: renovate.timer
+    name: "{{ item }}"
     state: started
     enabled: true
+  loop:
+    - renovate.timer
+    - renovate-cleanup.timer
   become: true