SetLargeCommunityMethod does not have 'large-community-set-ref'

[emil-palm]

I think this might be a just a oversight but SetLargeCommunityMethod struct does not have a 'large-community-set-ref' as the other version has: https://github.com/osrg/gobgp/blob/master/internal/pkg/config/bgp_configs.go#L5039

vs

https://github.com/osrg/gobgp/blob/master/internal/pkg/config/bgp_configs.go#L5148 and https://github.com/osrg/gobgp/blob/master/internal/pkg/config/bgp_configs.go#L5084

Should be a simple fix

[fujita]

Looks like an oversight. Updating gobgp.yang and adding such is fine by me but *community-set-ref isn't used by any code.