Resolve "Provide latest tag in Harbor stage"

This MR uses skopeo to copy the image from staging to prod with the latest tag for the most recent upload to harbor. This change has been tested locally with successful results for the ubi 7 test project: https://registry1.dsop.io/harbor/projects/4/repositories/opensource%2Fpipeline-test-project%2Fubi7 Closes #87 (closed)