fix: dont import covidcast in sir_complainsalot

Author: dshemetov

sir_complainsalot/delphi_sir_complainsalot/check_source.py

@@ -4,7 +4,6 @@
 from datetime import datetime, timedelta
 from typing import List
 
-import covidcast
 import pandas as pd
 from delphi_epidata import Epidata