Update what-is-discovery.md

Author: danielledennis

articles/external-attack-surface-management/what-is-discovery.md

@@ -3,7 +3,7 @@ title: What is Discovery?
 description: What is Discovery - Microsoft Defender External Attack Surface Management (Defender EASM) relies on our proprietary discovery technology to continuously define your organization’s unique Internet-exposed attack surface. 
 author: danielledennis
 ms.author: dandennis
-ms.service: security
+ms.service: defender-easm
 ms.date: 07/14/2022
 ms.topic: conceptual
 ---