Consider use of opencontainers spec metadata in container images

[planetf1]

          The opencontainers spec defines a list of standard annotations which could be used to add in important metadata. This superceeds the earlier label schema

See https://github.com/opencontainers/image-spec/blob/main/annotations.md

For instance this might be

LABEL org.opencontainers.image.version="5"

It may be worth opening a new issue just on this specific aspect

Originally posted by @planetf1 in https://github.com/open-quantum-safe/oqs-demos/pull/298#discussion_r1775072942