The other day I came across a nice dataset on COVID-19 cases in the US. I wrote some Mathematica code that included the following statement:

uscounties = 
  SemanticImport[
   "https://raw.githubusercontent.com/nytimes/covid-19-data/master/us-\
counties.csv"];

I aggregated the data by date and plotted a time series, which ended on March 28, the last date for which data were available. When I went back and ran the code the next day, it still plotted through March 28, even though when I downloaded the CVS data in my web browser, I could see that the data went through March 29. Restarting my computer cleared the cache, and the next time I ran the program I got the complete dataset. But resetting the computer seems a bit drastic. Is there a Mathematica statement to clear the cache? Is this what ClearSystemCache[] is for?