Fetches daily COVID-19 data for Afghanistan by province. Data from HDX https://data.humdata.org/dataset/afghanistan-covid-19-statistics-per-province. The cumulative data is stored in a Google sheet (https://docs.google.com/spreadsheets/d/1F-AMEDtqK78EA6LYME2oOsWQsgJi4CT3V_G4Uo-47Rg/export?format=csv), which is read as a CSV and sanitised.
get_afghan_regional_cases()
A data frame of daily Afghan provincial cases and deaths, stratified by state,
to be further processed by get_regional_data()
.