Update model retirement date to September 2025

Author: msakande

articles/ai-foundry/concepts/model-lifecycle-retirement.md

@@ -4,7 +4,7 @@ titleSuffix: Azure AI Foundry
 description: Learn about the lifecycle stages, deprecation, and retirement for Azure AI Foundry Models.
 ms.service: azure-ai-foundry
 ms.topic: concept-article
-ms.date: 06/17/2025
+ms.date: 09/17/2025
 ms.author: mopeakande
 manager: nitinme
 author: msakande