fix(build): `spinnaker` user/group id=1000 in Ubuntu image (#1465)
fix(build): `spinnaker` user/group id=1000 in Ubuntu image (#1465)

The slim/alpine image uses 1000/1000 as the uid and gid for the `spinnaker` user. Doing the same thing for the Ubuntu image makes it simpler for installers like the Helm chart to use either image variant.
spinnaker/halyard,spinnaker/halyard,spinnaker/halyard