fix instance value used by PodMonitor when selecting pods to monitor

Signed-off-by: Zina Rasoamanana <[email protected]>

Author: AnizR

content/docs/devops-tips/prometheus-metrics.md

@@ -47,7 +47,7 @@ spec:
       - key: app.kubernetes.io/instance
         operator: In
         values:
-        - release-name
+        - cert-manager
       - key: app.kubernetes.io/component
         operator: In
         values: