supersimple series plotter
character(1) must be found in dataset ProvinceState field, "" is typical for data aggregated only at country level, and that is the default
character(1) must be found in CountryRegion field
data.frame as returned by fetch_JHU_Data
passed to base::plot
none, used for side effects
An effort is made to change dates used as column names to lubridate date objects that are respected in plotting.
#plot_series(country="Italy")