Migrate nova-compute-vgpu to charmcraft-3.x

Ref: https://review.opendev.org/c/openstack/charm-nova-compute-nvidia-vgpu/+/962460

Author: freyes

charmed_openstack_info/data/lp-builder-config/openstack.yaml

@@ -784,7 +784,7 @@ projects:
       stable/2024.1:
         enabled: True
         build-channels:
-          charmcraft: "2.x/candidate"
+          charmcraft: "3.x/candidate"
         channels:
           - 2024.1/stable
         bases: