metrics-server: adding prometheus rules

Those rules were added later, I missed this change.

Signed-off-by: Beraldo Leal <[email protected]>

Author: beraldoleal

config/metrics/kustomization.yaml

@@ -2,3 +2,4 @@ resources:
   - metrics-deployment.yaml
   - metrics-service.yaml
   - metrics-servicemonitor.yaml
+  - metrics-prometheus-rules.yaml