Update Helm release loki to v6.12.0

Author: renovate[bot]

ops/monitoring/Chart.yaml

@@ -9,5 +9,5 @@ dependencies:
   version: 6.16.6
   repository: https://grafana.github.io/helm-charts
 - name: loki
-  version: 6.7.3
+  version: 6.12.0
   repository: https://grafana.github.io/helm-charts