Update ubcd url to https

Closes https://github.com/netbootxyz/netboot.xyz/issues/1263

roles/netbootxyz/defaults/main.yml

@@ -864,7 +864,7 @@ utilitiespcbios64:
     enabled: true
     name: Ultimate Boot CD (UBCD)
     type: memdisk
-    util_path: http://mirror.sysadminguide.net/ubcd/ubcd539.iso
+    util_path: https://mirror.sysadminguide.net/ubcd/ubcd539.iso
     version: '539'
 wimboot_location: http://${boot_domain}/wimboot
 wimboot_upstream_url: https://github.com/ipxe/wimboot/releases/latest/download/wimboot