chore(deps): update helm release kube-prometheus-stack to v78.4.0 (#843)

Co-authored-by: renovate[bot] <29139614+renovate[bot]@users.noreply.github.com>

Author: renovate[bot]

kubernetes-services/templates/prometheus.yaml

@@ -13,7 +13,7 @@ spec:
   sources:
     - chart: kube-prometheus-stack
       repoURL: https://prometheus-community.github.io/helm-charts
-      targetRevision: 78.3.2
+      targetRevision: 78.4.0
       helm:
         values: |
           prometheusOperator: