Fix virtualbox network configuration with modern Ruby

WSL with Virtualbox provider it works with this modification.

vagrant/lib/forklift/box_distributor.rb

@@ -295,7 +295,7 @@ def configure_virtualbox(machine, box, networks = [])
         end
 
         networks.each do |network|
-          override.vm.network network['type'], network['options']
+          override.vm.network network['type'], **network['options']
         end
 
         merged_options(box, 'virtualbox_options').each do |opt, val|