Update doc's front matter date

Author: andrewconnell

docs/spfx/web-parts/get-started/using-web-part-as-ms-teams-tab.md

@@ -1,7 +1,7 @@
 ---
 title: Building Microsoft Teams tab using SharePoint Framework - Tutorial
 description: Tutorial on how to build Microsoft Teams tabs using SharePoint Framework. Capability was released to general availability in SharePoint Framework v1.8.
-ms.date: 02/08/2020
+ms.date: 03/31/2020
 ms.prod: sharepoint
 localization_priority: Priority
 ---