Changing labels to group by (#1203)

* rhacs_instance_id -> namespace: not all alerts have rhacs_instance_id
* add severity: don't want to group alerts with different severities together

dp-terraform/helm/rhacs-terraform/charts/observability/templates/01-operator-03-secret-alertmanager.yaml

@@ -12,6 +12,7 @@ stringData:
       repeat_interval: 12h
       group_by:
       - cluster_id
+      - severity
       routes:
       - receiver: managed-rhacs-deadmanssnitch
         repeat_interval: 5m
@@ -21,9 +22,10 @@ stringData:
           observability: managed-rhacs
       - receiver: managed-rhacs-pagerduty
         group_by:
-        - rhacs_instance_id
+        - namespace
+        - severity
         matchers:
-        - "rhacs_instance_id =~ \".*\""
+        - "namespace =~ \"rhacs-.*\""
     receivers:
     - name: managed-rhacs-pagerduty
       pagerduty_configs: