Update bastion-overview.md

taking preview tag out for GA

Author: aatsang

articles/bastion/bastion-overview.md

@@ -51,7 +51,7 @@ The following diagrams show the available architectures for Azure Bastion.
 
 :::image type="content" source="./media/quickstart-developer-sku/bastion-shared-pool.png" alt-text="Diagram that shows the Azure Bastion developer SKU architecture." lightbox="./media/quickstart-developer-sku/bastion-shared-pool.png":::
 
-**Private-only deployment (Preview)**
+**Private-only deployment**
 
 :::image type="content" source="./media/private-only-deployment/private-only-architecture.png" alt-text="Diagram showing Azure Bastion private-only architecture." lightbox="./media/private-only-deployment/private-only-architecture.png":::