doe RFC3339 accept date only? If not, we should accept a date in RFC3339 structure, but with only the date..
It seems that time.RFC3339 doesn't support an ISO 8601 date structure with only the date, but we could nest two time.Parses (one with time.RFC3339 and the other with "2006-01-02") or we could use dateparse.ParseAny.
edit: dateparse is also in go.mod.
@YakoYakoYokuYoku Sounds good to me to have "2006-01-02" and RFC3339 as fallback. I'd avoid another dependency
Scratch that, we already have dateparse 🙃 Lets go for dateparse.ParseLocal