Update configmap-monitoring.yaml (#596)

Add a new metric that will allow Prometheus to scrape the stale machine count

charts/internal/machine-controller-manager/seed/templates/configmap-monitoring.yaml

@@ -26,7 +26,7 @@ data:
         target_label: pod
       metric_relabel_configs:
       - source_labels: [ __name__ ]
-        regex: ^(mcm_cloud_api_requests_failed_total|mcm_cloud_api_requests_total|mcm_machine_controller_frozen|mcm_machine_current_status_phase|mcm_machine_deployment_failed_machines|mcm_machine_items_total|mcm_machine_set_failed_machines|mcm_machine_deployment_items_total|mcm_machine_set_items_total|mcm_scrape_failure_total|process_max_fds|process_open_fds|mcm_workqueue_adds_total|mcm_workqueue_depth|mcm_workqueue_queue_duration_seconds_bucket|mcm_workqueue_queue_duration_seconds_sum|mcm_workqueue_queue_duration_seconds_count|mcm_workqueue_work_duration_seconds_bucket|mcm_workqueue_work_duration_seconds_sum|mcm_workqueue_work_duration_seconds_count|mcm_workqueue_unfinished_work_seconds|mcm_workqueue_longest_running_processor_seconds|mcm_workqueue_retries_total)$
+        regex: ^(mcm_cloud_api_requests_failed_total|mcm_cloud_api_requests_total|mcm_machine_controller_frozen|mcm_machine_current_status_phase|mcm_machine_deployment_failed_machines|mcm_machine_items_total|mcm_machine_set_failed_machines|mcm_machine_deployment_items_total|mcm_machine_set_items_total|mcm_machine_set_stale_machines_total|mcm_scrape_failure_total|process_max_fds|process_open_fds|mcm_workqueue_adds_total|mcm_workqueue_depth|mcm_workqueue_queue_duration_seconds_bucket|mcm_workqueue_queue_duration_seconds_sum|mcm_workqueue_queue_duration_seconds_count|mcm_workqueue_work_duration_seconds_bucket|mcm_workqueue_work_duration_seconds_sum|mcm_workqueue_work_duration_seconds_count|mcm_workqueue_unfinished_work_seconds|mcm_workqueue_longest_running_processor_seconds|mcm_workqueue_retries_total)$
         action: keep
 
   alerting_rules: |