LP#1732275: add release notes entry

LP#1732275: add release notes entry

To test the page series:

[1] Create a patron that has at least two loans, one that is
    overdue by 7 days and one that will be due in 3 days.
[2] Activate the '3 Day Courtesy Notice' and '7 Day Overdue Email Notification'
    action trigger events, then generate events for those two loans
    by running something like this:

    action_trigger_runner.pl --hooks=checkout.due --process-hooks
    action_trigger_runner.pl --run-pending

    Note that --run-pending is needed to ensure that the events are
    complete, as the new columns include only checkout.due events
    that are complete. (Pending ones don't count because no notification
    would have yet made its way to the patron.)
[3] Apply the patch.
[4] Verify that the patron Items Out grid in the web staff client
    now has Total Notices and Last Notice columns respectively
    including the count of notices and the date of the last one.
[5] Turn on the webstaff.circ.itemsout_notice_count_excludes_courtesies
    library setting and refresh the grid. This time, the courtesy notice
    event should not be reflected by those two columns.

Signed-off-by: Galen Charlton <gmc@equinoxinitiative.org>