Update shared-channels.md

Teams/shared-channels.md

@@ -197,6 +197,9 @@ For information about how to prepare your app for shared channels, see [Microsof
 
 The following apps are supported for use in shared channels. 
 
+> [!NOTE]
+> The following apps are supported for use in production environment. To ensure your app supports Government Community Cloud (GCC), GCC-High, and Department of Defense (DOD) environments, [enable shared channels in your app](/microsoftteams/platform/concepts/build-and-test/shared-channels).
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