fix metrics-monitor.yaml

Author: googs1025

chart/templates/metrics-monitor.yaml

@@ -1,4 +1,7 @@
-{{- if .Values.prometheus.enable -}}
+{{- if .Values.prometheus.enable }}
+{{- if not (.Capabilities.APIVersions.Has "monitoring.coreos.com/v1/ServiceMonitor") }}
+{{- fail "The cluster does not support the required API resource `monitoring.coreos.com/v1/ServiceMonitor`." }}
+{{- end }}
 apiVersion: monitoring.coreos.com/v1
 kind: ServiceMonitor
 metadata: