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

keycloak is a critical service
separating keycloak updates makes it easier to respond quickly to
critical updates or delay them when there are breaking changes

renovate.json

@@ -29,13 +29,20 @@
     // https://docs.renovatebot.com/presets-default/#automergestablenonmajor
     {
       "groupName": "all stable non-major dependencies",
-      "groupSlug": "all-stable-minor-patch",
+      "groupSlug": "all-stable-minor",
       "matchCurrentVersion": "!/^0/",
       "matchUpdateTypes": [
-        "minor",
+        "minor"
-        "patch"
+      ],
+      "excludePackageNames": [
+        "git.hamburg.ccc.de/ccchh/oci-images/keycloak"
       ]
     },
+    {
+      "matchUpdateTypes": ["patch"],
+      "matchCurrentVersion": "!/^0/",
+      "automerge": true
+    },
     {
       "matchDatasources": ["docker"],
       "matchPackageNames": ["docker.io/pretix/standalone"],

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: