With the release of GNOME 3.28, as always we will defer until the release of a .1. This task serves the purpose of acknowledging that GNOME 3.28 exists and it's on our radar to perform a stack upgrade.
This stack upgrade is not a priority and will need to be done alongside releasing another Budgie release that has GNOME 3.28 compatibility and introduces features like our own desktop icon implementation (given that's been deprecated from Nautilus), as well as accounting for any GNOME Settings Daemon and Mutter changes.