example json file needs abbreviation in units

[nickreich]

This file https://github.com/reichlab/docs.zoltardata/blob/master/docs/zoltar-project-config.json does not comport with the required "abbreviation" field needed in units, per documentation here: https://docs.zoltardata.com/fileformats/#project-creation-configuration-json

[nickreich]

Also, I think the "unit" field in the targets section is not valid either. Per description on this page, "unit" is not a valid field name for a target, and yet it is present in the config file above.

[matthewcornell]

This should do it: updated out-of-date zoltar-project-config.json