fix: argocd metrics port name, coredns metrics via headless service

otc/observability.buildth.ing/stacks/observability/victoria-k8s-stack/manifests/argocd-scrape.yaml

@@ -10,4 +10,4 @@ spec:
     matchLabels:
       app.kubernetes.io/part-of: argocd
   endpoints:
-    - port: metrics
+    - port: http-metrics

otc/observability.buildth.ing/stacks/observability/victoria-k8s-stack/manifests/coredns-scrape.yaml

@@ -1,5 +1,22 @@
+apiVersion: v1
+kind: Service
+metadata:
+  name: coredns-metrics
+  namespace: kube-system
+  labels:
+    k8s-app: coredns-metrics
+spec:
+  clusterIP: None
+  selector:
+    k8s-app: coredns
+  ports:
+    - name: metrics
+      port: 9153
+      targetPort: 9153
+      protocol: TCP
+---
 apiVersion: operator.victoriametrics.com/v1beta1
-kind: VMPodScrape
+kind: VMServiceScrape
 metadata:
   name: coredns
 spec:
@@ -8,7 +25,6 @@ spec:
       - kube-system
   selector:
     matchLabels:
-      k8s-app: coredns
-  podMetricsEndpoints:
-    - targetPort: 9153
-      path: /metrics
+      k8s-app: coredns-metrics
+  endpoints:
+    - port: metrics