Update Helm release kube-prometheus-stack to v70.9.0

Author: renovate[bot]

k8s/turingpi/apps/monitoring/kube-prometheus-stack/app/helmrelease.yaml

@@ -9,7 +9,7 @@ spec:
   chart:
     spec:
       chart: kube-prometheus-stack
-      version: 70.8.0
+      version: 70.9.0
       sourceRef:
         kind: HelmRepository
         name: prometheus-community