Add weekly test to check that contamination files are up-to-date

[namurphy]

Related to #74 and #77, it would be helpful to add a cron test that takes a date approximately 1.5–2 months prior to the date the test is being run, and makes sure that we're able to get a temperature response. This would serve as a reminder for when we need to update the contamination data files.

This would only be a temporary hack, as we need to figure out a longer term solution for making sure that the contamination data files are kept up-to-date.