Changed the published_datetime field of stix.exploit_target.vulnerability.Vulnerability to be wrapped in a property descriptor, analogously to discovered_datetime.  This fixes python-stix issue #276.
Changed the published_datetime field of
stix.exploit_target.vulnerability.Vulnerability
to be wrapped in a property descriptor, analogously to
discovered_datetime.  This fixes python-stix issue #276.

STIXProject/python-stix