Buildah requires privileges and capabilities

[codingben]

When buildah is running inside Kubernetes pod, it requires root privileges. Also, building using buildah requires a properly installed shadow-utils package (which in turn requires SETFCAP).

So we have a few issues:

• Buildah requires root privileges
• Buildah requires SETFCAP capability

Root privileges can be solved, but there is no workaround to not setting SETFCAP capability (in security contexts).

[codingben]

Currently I'm investigating an option to not use buildah, and use directly github.com/google/go-containerregistry to build image from scratch and then push it.

[codingben]

Opened PR: #4