[Rspamd] meta_exporter: return false if not matched

[Compose] Update Dovecot image

data/conf/rspamd/local.d/metadata_exporter.conf

@@ -20,7 +20,7 @@ return function(task)
   if ratelimited then
     return true
   end
-  return
+  return false
 end
 EOD;
 }

docker-compose.yml

@@ -169,7 +169,7 @@ services:
             - sogo
 
     dovecot-mailcow:
-      image: mailcow/dovecot:1.68
+      image: mailcow/dovecot:1.69
       build: ./data/Dockerfiles/dovecot
       cap_add:
         - NET_BIND_SERVICE