publish_pages not working for development app

I'm trying to make an app that will allow blog posts from my website to be published to a Facebook page which I am the admin of.

Obviously I need the publish_pages and manage_pages permission to do this and I need to provide a screencast showing how these permissions will be used.

From my understanding, I can still publish a post from my website to my Facebook page while the app is in development mode as long as I am the admin of the page (which I am) but the posts won't be visible to the public.

So I complete the authentication process here (see below).

Finally I add my blog post. However, I then get the following as an error message

"(#200) The permission(s) publish_actions are not available. It has been deprecated. If you want to provide a way for your app users to share content to Facebook, we encourage you to use our Sharing products instead."

Would this be an issue with the system I am using, making a depreciated API call?

Deprecation:

The publish_actions permission will be deprecated. This permission granted apps access to publish posts to Facebook as the logged in user. Apps created from today onwards will not have access to this permission. Apps created before today that have been previously approved to request publish_actions can continue to do so until August 1, 2018. No further apps will be approved to use publish_actions via app review. Developers currently utilizing publish_actions are encouraged to switch to Facebook's Share dialogs for web, iOS and Android.

From now on you can only publish to your own facebook profile not facebook page. For more information you can visit their official documentation