incorrect value in dhcp-relay example

[LuPo]

Documentation for CL v5.5 reports incorrect attribute gateway instead of giaddress

cumulus@DC-Spine02:mgmt:~$ nv set service dhcp-relay default source-ip 
auto       giaddress  
cumulus@DC-Spine02:mgmt:~$ nv set service dhcp-relay default source-ip giaddress 
cumulus@DC-Spine02:mgmt:~$ nv config diff 
- set:
    service:
      dhcp-relay:
        default:
          source-ip: giaddress