Correct error in metadata test

It should not be possible to have two signals with the same source,
signal, time_type, and geo_type. This will cause a query for that signal
to have two metadata rows attached to the covidcast_signal data frame,
which will confuse everything.

Author: capnrefsmmat

R-packages/covidcast/tests/testthat/api.covidcast.cmu.edu/epidata/api.php-dd024f.csv

@@ -1,3 +1,3 @@
 data_source,signal,time_type,geo_type,min_time,max_time,min_value,max_value,max_issue
 foo,bar,day,county,20200101,20200102,0,10,20200404
-foo,bar,day,county,20201002,20201003,0,10,20201101
+foo,bar,day,state,20201002,20201003,0,10,20201101

R-packages/covidcast/tests/testthat/test-covidcast.R

@@ -52,7 +52,7 @@ with_mock_api({
                      max_value = 10,
                      num_locations = 100,
                      time_type = "day",
-                     geo_type = "county",
+                     geo_type = c("county", "state"),
                      max_issue = as.Date(c("2020-04-04", "2020-11-01"))
                    ),
                    class = c("covidcast_meta", "data.frame")