Ability to add custom json fields to artifact metadata

[vanosg]

What would you like to be added?

Thanks for the great maintenance on this action, and apologies if this already exists, but I couldn't find anything relevant in the documentation! We would find this even more useful if the user was able to add an additional custom metadata field when uploading an artifact. This field(s) could contain information such as the build/version that the artifact came from, or other logging/description associated with the generation of the artifact.

Why is this needed?

The particular use case we have is to manually review queried artifacts and review a summary/description of the information inside the artifact, without needing to download all the artifacts present to extract the data.

Any effort you could dedicate to this, or existing methods to accomplish something similar, would be much appreciated, thank you!