add get_public_ip method to sliver object
add get_public_ip method to sliver object

cboling/xos,opencord/xos,zdw/xos,opencord/xos,zdw/xos,opencord/xos,cboling/xos,zdw/xos,zdw/xos,open-cloud/xos,cboling/xos,cboling/xos,open-cloud/xos,open-cloud/xos,cboling/xos