Update New-CsAutoAttendant.md

Author: CLYVR

teams/teams-ps/MicrosoftTeams/New-CsAutoAttendant.md

@@ -396,7 +396,7 @@ Aliases:
 
 Required: False
 Position: Named
-Default value: None
+Default value: Echo
 Accept pipeline input: False
 Accept wildcard characters: False
 ```