Update prometheus to v3.9.1

Author: mkjpryor

ansible/roles/linux-monitoring/defaults/main.yml

@@ -17,7 +17,7 @@ grafana_dashboards:
 
 prometheus_container_image_prefix: "docker.io"
 
-prometheus_version: "v3.5.0"
+prometheus_version: "v3.9.1"
 
 prometheus_container_image_name: "prom/prometheus"