Downgrade blubber to 1.0.1
We updated blubber from 0.16.0 to 1.1.0, but now while the regular builds in CI pass, the tagged builds on production runners fail very early in the build, before even reading the Dockerfile.
Make a wild guess that the problem is with the most recent release of blubber, downgrade to 1.0.1 which we see is in use and working on other builds.