Move mailu's resolver to Mailu 2024.06.63, which follows the root key change

The root zone signs with KSK-2024 since 2026-10-11. The pinned resolver
image (2024.06.59) trusted only KSK-2017 and kept its anchor inside the
container, so every lookup failed with SERVFAIL and mail was refused or
stuck (issue 687). 2024.06.63 refreshes the anchor with unbound-anchor at
every start and fails its health check on SERVFAIL, which the old
'dig @127.0.0.1' never did (issue 688).

modules/mailu/module.json

@@ -371,7 +371,7 @@
       "id": "resolver",
       "type": "container",
       "name": "mailu-resolver",
-      "image": "ghcr.io/mailu/unbound@sha256:3a0fdfb364a63f4f9259526e013c1ef40f5f14de3621ce1560804b3a5909584a",
+      "image": "ghcr.io/mailu/unbound@sha256:2c037bc5c988b5c0ab7e1b6e6ffa762e14ba1e45c96281ac87f8b9be8eee8b6e",
       "health": {
         "kind": "runtime"
       },