fixed date

Author: rwike77

articles/active-directory/develop/reference-aadsts-error-codes.md

@@ -13,7 +13,7 @@ ms.workload: identity
 ms.tgt_pltfrm: na
 ms.devlang: na
 ms.topic: reference
-ms.date: 02/19/20
+ms.date: 02/19/2020
 ms.author: ryanwi
 ms.reviewer: hirsin
 ms.custom: aaddev