Adding new ap-southeast-3 AWS region

Source commit: 066fcecf63ac590eae3522137d6a6b37b2c6d30e

source/forms/SiteAdvanced.dfm

@@ -1059,6 +1059,7 @@ object SiteAdvancedDialog: TSiteAdvancedDialog
               'ap-south-1'
               'ap-southeast-1'
               'ap-southeast-2'
+              'ap-southeast-3'
               'ca-central-1'
               'cn-north-1'
               'cn-northwest-1'