build(helm): update rook-ceph to v1.18.6

Author: renovate-bot

apps/versions.toml

@@ -76,7 +76,7 @@ helm = "https://charts.bitnami.com/bitnami"
 chart = "rabbitmq-cluster-operator"
 
 [rook]
-version = "1.17.7"
+version = "v1.18.6"
 helm = "https://charts.rook.io/release"
 chart = "rook-ceph"