fix(helm): update chart grafana to 7.3.12 (#6355)

| datasource | package | from   | to     |
| ---------- | ------- | ------ | ------ |
| helm       | grafana | 7.3.11 | 7.3.12 |

Co-authored-by: rosey-the-renovator-bot[bot] <98764075+rosey-the-renovator-bot[bot]@users.noreply.github.com>

kubernetes/main/apps/monitoring/grafana/app/helmrelease.yaml

@@ -10,7 +10,7 @@ spec:
   chart:
     spec:
       chart: grafana
-      version: 7.3.11
+      version: 7.3.12
       sourceRef:
         kind: HelmRepository
         name: grafana-charts