Require Automatic Updates 4.x

Marking as RTBC assuming tests will turn green.

As both tags are in the stable release branches we already depend on, this is no longer a stable blocker. However, this should go in anyway just to make the requirements concrete and prevent Composer from accidentally choosing older versions.

Merged into 1.x and cherry-picked to 1.0.x.

Automatically closed - issue fixed for 2 weeks with no activity.