Update registry location for elastic agent packages

Author: karenzone

reference/fleet/add-fleet-server-kubernetes.md

@@ -336,7 +336,7 @@ Adapt and change the suggested manifests and deployment strategy to your needs,
           automountServiceAccountToken: false
           containers:
           - name: elastic-agent
-            image: docker.elastic.co/beats/elastic-agent:{{version.stack}}
+            image: docker.elastic.co/elastic-agent:{{version.stack}}
             env:
               - name: FLEET_SERVER_ENABLE
                 value: "true"
@@ -422,7 +422,7 @@ Adapt and change the suggested manifests and deployment strategy to your needs,
           automountServiceAccountToken: false
           containers:
           - name: elastic-agent
-            image: docker.elastic.co/beats/elastic-agent:{{version.stack}}
+            image: docker.elastic.co/elastic-agent:{{version.stack}}
             env:
               - name: FLEET_SERVER_ENABLE
                 value: "true"