update frequency in portal "Additional Info" section

[jmc39]

RE: data.sandiego.gov

In the "Additional Info" section add info for the frequency the data set is updated. It is not self-evident from the "date issued" and "data modified" how frequent the data is updated (see embedded screen snippet). In connecting a csv URL to a Carto map, it is uncertain how frequently the dataset should be sync (e.g.
http://seshat.datasd.org/pd/pd_collisions_datasd.csv).