update to latest date

[rahulbot]

This app currently still uses 2010 5-year average ACS data. It would be great o update this to 2020 data. Also the instructions for acquiring the data are out of date, because the Census Bureau has changed its website. This issue would require finding and downloading a new set of US Foreign-Born population data, hopefully broken down by zip-code still. Then we'd have to update the data import script to create a database from this new dataset, and also update the instructions for fetching data to match the new Census website setup.