update latest docker image URL
update latest docker image URL

now includes tgz

[#117827631]

Signed-off-by: Maria Shaldibina <dc03896a0185453e5852a5e0f0fab6cbd2e026ff@pivotal.io>

ggeorgiev/docker-image-resource,concourse/docker-image-resource,SillyMoo/docker-image-resource,SillyMoo/docker-image-resource,barthy1/docker-image-resource,ggeorgiev/docker-image-resource,barthy1/docker-image-resource,concourse/docker-image-resource