Adding new ap-southeast-4 AWS region

Source commit: 9907c244690e7202aa80a1583f624e49d3856481

source/forms/SiteAdvanced.dfm

@@ -1062,6 +1062,7 @@ object SiteAdvancedDialog: TSiteAdvancedDialog
               'ap-southeast-1'
               'ap-southeast-2'
               'ap-southeast-3'
+              'ap-southeast-4'
               'ca-central-1'
               'cn-north-1'
               'cn-northwest-1'