Update Add-CsSlaDelegates.md

Author: przlplx

skype/skype-ps/skype/Add-CsSlaDelegates.md

@@ -1,7 +1,7 @@
 ---
 external help file: Microsoft.Rtc.Management.dll-help.xml
 online version: https://learn.microsoft.com/powershell/module/skype/add-cssladelegates
-applicable: Skype for Business Server 2015, Skype for Business Server 2019
+applicable: Skype for Business Server 2013, Skype for Business Server 2015, Skype for Business Server 2019
 title: Add-CsSlaDelegates
 schema: 2.0.0
 manager: rogupta