Update docker.io/library/postgres Docker tag to v15

Closes #130

Also add appropriate config for renovate to upgrade Hedgedoc.

inventories/chaosknoten/host_vars/pad.yaml

@@ -11,3 +11,6 @@ nginx__version_spec: ""
 nginx__configurations:
   - name: pad.hamburg.ccc.de
     content: "{{ lookup('ansible.builtin.file', 'resources/chaosknoten/pad/nginx/pad.hamburg.ccc.de.conf') }}"
+
+# renovate: datasource=docker depName=quay.io/hedgedoc/hedgedoc
+host_pad__docker_compose__hedgedoc_version: 1.11.1

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

@@ -62,7 +62,7 @@ services:
       - POSTGRES_DB=mailmandb
       - POSTGRES_USER=mailman
       - "POSTGRES_PASSWORD={{ secret__lists__postgres_password }}"
-    image: docker.io/library/postgres:12-alpine
+    image: docker.io/library/postgres:15-alpine
     volumes:
       - /opt/mailman/database:/var/lib/postgresql/data
     networks:

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

@@ -13,7 +13,7 @@ services:
     restart: unless-stopped
 
   app:
-    image: quay.io/hedgedoc/hedgedoc:1.11.0
+    image: quay.io/hedgedoc/hedgedoc:{{ host_pad__docker_compose__hedgedoc_version }}
     environment:
       - "CMD_DB_URL=postgres://hedgedoc:{{ secret__hedgedoc_db_password }}@database:5432/hedgedoc"
       - "CMD_DOMAIN=pad.hamburg.ccc.de"