Metacat

We need to automatically insert pubDate on registry submission. The 'pubDate'
field represents the date that the resource was published. The format should be
represented as: CCYY, which represents a 4 digit year, or as CCYY-MM-DD, which
denotes the full year, month, and day. Note that month and day are optional
components. Formats must conform to ISO 8601

Updated and new version of data packages that have been submitted to the
registry will have a new pubDate.

IRQ conversation, " yeah, an updated document is really a new version with a new
date the (modified) resource was published <matt> so it should proabbly be
updated <matt> the original revision will still have the original pubDate
<matt> so nothing is lost"

Note: This will be used for citations and will be used with citation information
in stylesheets along with the lsid on the ESA stylesheet.