Update builder workflows

[dmikusa]

The workflow that is updating the builder is a one-off workflow. This was done because at the time the standard pipeline-builder workflow for updating a builder was not capable of running in a repo that was both a composite buildpack and a builder. This has since been fixed and the standard workflow should be OK for both in the same repo.

In addition, we should remove the update-lifecycle workflow. This isn't needed because our builder is not specifying a lifecycle, it's using the default one provided by pack.

This issue is a reminder to move back to the standard workflows.