Please do add support for custom post types. As noted in this request two years ago, the fix is very simple, just one line added to the defaults. If you simply include
'post_type' => 'page', in the default array, then we can override that default with something like
[child-pages post_type='articles'] to support our own custom post types. The change has no ill effects or backward compatibility issues.
Custom post types are now more common than they were two years ago, since recent versions of WordPress have made using them easier. Please include this fix in your next update of List Pages Shortcode so that we don't have to patch the code after each update.