chore: update Dynatrace docs to reflect the Kubernetes reality

Author: msvolenski

content/en/docs/deployment/mendix-cloud-deploy/monitoring-with-apm/dynatrace-metrics.md

@@ -60,7 +60,8 @@ What Dynatrace calls "dimensions," other monitoring tools call "tags." The Mendi
 For metrics that are pushed to Dynatrace, Mendix attaches these default dimensions:
 
 * `app` – The environment ID of your Mendix environment
-* `instance_index` – Instance index that the metrics belong to
+* `pod_name` - The instance to which the metrics belong (available only in Kubernetes deployments)
+* `instance_index` – Instance index that the metrics belong to (available only in Cloud Foundry deployments)
 
 #### Extra Dimensions