I update the CSV file every weekday at 12 PM when I receive an official email from the mailing list I signed up for at Allegheny Alerts.
You can view my graphs generated from this data at https://franklinchen.github.io/covid-19-allegheny-county/ (updated daily).
Also, please consult https://www.alleghenycounty.us/Health-Department/Resources/COVID-19/COVID-19.aspx for official visualizations.