Update all stable non-major dependencies

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

@@ -15,7 +15,7 @@ services:
       - pretalx_net
 
   redis:
-    image: docker.io/library/redis:8.6.2
+    image: docker.io/library/redis:8.6.1
     restart: unless-stopped
     volumes:
       - redis:/data
@@ -23,7 +23,7 @@ services:
       - pretalx_net
 
   static:
-    image: docker.io/library/nginx:1.29.7
+    image: docker.io/library/nginx:1.29.6
     restart: unless-stopped
     volumes:
       - public:/usr/share/nginx/html