I have set it to (All Versions) just because there is no option for "future versions".
This post is for archive sake so it is not a demand to get it done as I have talked to Klemen about the support for this and at the time of this post (2019/07/20), there is no support for controlling a rideable mob.
The community would eventually like Mob riding controls using (W, S, A, D, and Space) controls in procedures or a way to enable controls to move the mob around like a horse, mule or donkey.
Again no rush this is just to help keep track of this request until the feature can be figured out to how to add support for this feature.
Issue comments
That would be amazing! a way to control mobs like horses (with the W, A, S, D and SPACE keys) without the need to use horse AI, since using it we must also use a cell to mount the mob, which It's bad considering you might want to mob for another purpose (like a car for example).
Thank you for opening a ticket for this so we can track this and see the demand for this based on the upvotes.