Compressed docker image not recognized in docker pipeline

[pombredanne]

I tried to scan this as a docker image: https://github.com/nyph-infosec/daggerboard/releases/download/v1.0.1/daggerboard_docker_image_v1-0-1.tgz and nothing happened. This is a docker "saved" image that's been gzipped and renamed to .tgz

[tdruez]

Looking at https://github.com/nexB/scancode.io/blob/main/scanpipe/pipes/docker.py#L48 and prior changes, it seems that we never supported the .tgz extension.

It should be fairly easy to update the glob pattern to capture .tgz along tars, assuming the container_inspector.utils.extract_tar supports tgz as well.