Change NTD monthly schedule to run every Monday

instead of every day.

There is no need to run every day since it is a
monthly file, but having the process
running once a week give us a better window to
add and process new files once it is released.

[#3519]

airflow/dags/sync_ntd_data_xlsx/METADATA.yml

@@ -1,5 +1,5 @@
-description: "Scrape tables from DOT Ridership XLSX file daily"
-schedule_interval: "0 10 * * *" # 10am UTC every day
+description: "Scrape tables from DOT Ridership XLSX file weekly"
+schedule_interval: "0 10 * * 1" # 10am UTC every Monday
 tags:
   - all_gusty_features
 default_args: