[zope] Zope 5.8 released

On behalf of Zope developer community I am pleased to announce the release of Zope 5.8. PLEASE NOTE: This release drops support for Python 3.6. It has been in end-of-life status for a while and supporting it is becoming harder and harder as the infrastructure and software we use for CI is dropping support for it. It also fixes a cache server interoperability issue introduced in release 5.7.1 and a bug on the History tab in the ZMI. For the full list of changes see the change logs at https://zope.readthedocs.io/en/latest/changes.html#id1 Installation instructions can be found at https://zope.readthedocs.io/en/latest/INSTALL.html. Jens Vagelpohl