chore(kube): bump stalwartlabs/stalwart Docker tag to v0.16.21

docker/personal/tandoor/docker-compose.yml

@@ -9,7 +9,7 @@ services:
 
   web_recipes:
     restart: always
-    image: vabene1111/recipes:2.6.15
+    image: vabene1111/recipes:2.6.13
     networks:
       - default
       - proxy

kubernetes/infrastructure/mail/stalwart/values.yaml

@@ -7,7 +7,7 @@
 # Container image
 image:
     repository: stalwartlabs/stalwart
-    tag: v0.16.20
+    tag: v0.16.21
     pullPolicy: IfNotPresent
 # Single-node RocksDB deployment.
 replicaCount: 1