Hub-metadata file

[harryhoch]

The directory structure specifies that admin.json and tasks.json should be JSON files, but model-metadata-schema.json can be a JSON or yaml file.

Clarification is needed here. At the very least, change to say "model-metadata-schema.{json,yml} is a JSON or YAML file". More generally, can we allow both formats for all 3 config files? If not, we should explain why?

[mzorn-58]

Will admin.json and tasks.json be able to be a YAML file? If not, why not? https://hubdocs.readthedocs.io/en/latest/format/hub-config.html

[micokoch]

I couldn't find any references to model-metadata-schema being a yaml file, and all uses seem to require it to be a JSON file. So, I removed mention of it being a YAML file and linked to the appropriate reference in #102 . I think this resolves this issue, and so I will close it.