Use of a pattern to filter downloads

[krachlin]

Would like to be able to use a pattern for the filenames to limit what is downloaded from a collection.

For example, download only files that begin with GSM using -filename option (at end of below)
podaac-data-subscriber -c GRACEFO_L2_JPL_MONTHLY_0061 -d ./ --start-date 2018-05-22T00:00:00Z -e "" -filename "GSM*"