update Azure Web App runtime stack to DOTNETCORE (#12833)

* update Azure Web App runtime stack to DOTNETCORE

Updated Notes, which will help user to update their Azure Web App runtime Stack to DOTNETCORE

* Update src/Websites/Websites/help/Set-AzWebApp.md

Co-authored-by: Mike F. Robbins <[email protected]>

Co-authored-by: Mike F. Robbins <[email protected]>

Author: inmishrar

src/Websites/Websites/help/Set-AzWebApp.md

@@ -561,7 +561,15 @@ This cmdlet supports the common parameters: -Debug, -ErrorAction, -ErrorVariable
 ### Microsoft.Azure.Commands.WebApps.Models.PSSite
 
 ## NOTES
+Below provided cmdlet will help you to update Azure Web App to **DOTNETCORE**
 
+$PropertiesObject = @{
+    "CURRENT_STACK" =  "dotnetcore"
+}
+New-AzResource -PropertyObject $PropertiesObject -ResourceGroupName "Default-Web-WestUS" -ResourceType Microsoft.Web/sites/config -ResourceName "ContosoWebApp/metadata" -ApiVersion 2018-02-01 -Force
+
+Replace the values of Default-Web-WestUS with your resource group name of the webapp and ContosoWebApp with the webapp name.
+ 
 ## RELATED LINKS
 
 [Get-AzWebApp](./Get-AzWebApp.md)
@@ -575,3 +583,5 @@ This cmdlet supports the common parameters: -Debug, -ErrorAction, -ErrorVariable
 [Start-AzWebApp](./Start-AzWebApp.md)
 
 [Stop-AzWebApp](./Stop-AzWebApp.md)
+
+[New-AzResource](./New-AzResource.md)