Adding labels to containers build by devcontainer cli that are based on a Dockerfile (instead of an image) does not work

[Roemer]

A few months ago, the --label property to build was added that adds labels (#846). Unfortunately it seems that this only works when a devcontainer is build that is based directly from an image. If it is based from a Dockerfile, the labels from --label are not added.
I added a test in a PR that shows the problem, see here: #929

[chrmarti]

Commented on the PR.

[jmcombs]

Is there a workaround for this, at the moment?