Add mandatory endpoints field

  Fixes: error validating "": error validating data:
ValidationError(ServiceMonitor.spec): missing required field
"endpoints" in com.coreos.monitoring.v1.ServiceMonitor.spec

Signed-off-by: Dinar Valeev <k0da@opensuse.org>

chart/k8gb/templates/servicemonitor.yaml

@@ -6,6 +6,8 @@ metadata:
   labels:
     {{- include "chart.labels" . | nindent 4 }}
 spec:
+  endpoints:
+  - port: metrics
   selector:
     matchLabels:
       {{- include "chart.selectorLabels" . | nindent 6 }}