[datasource] Add support for base image deprecation #231
Description
What would you like to be added:
Motivated by this LinkedIn post by Rory McCune
We should be able to identify and flag deprecated base images. There is work in the oci-spec around annotations to signal deprecation, but it's not yet completed. opencontainers/image-spec#903
An alternative would be of Dockerhub or other registries supported a deprecation flag.