Update Helm release promtail to v6.16.6

Author: renovate[bot]

ops/monitoring/Chart.yaml

@@ -6,7 +6,7 @@ dependencies:
   version: 0.24.3
   repository: https://victoriametrics.github.io/helm-charts/
 - name: promtail
-  version: 6.16.4
+  version: 6.16.6
   repository: https://grafana.github.io/helm-charts
 - name: loki
   version: 6.7.3