Enable bionic build replacing xenail Enable bionic 18.04 replacing xenial 16.04. Curl https://oligarchy.co.uk/xapian/ is failing to validate the SSL cert with the CA on xenial. See if this fixes it. Python 3.4 is not supported on bionic is obsolete so remove testing. It was retained because 3.4 was EPEL version for centos 7. With centos demise, removed it from 'python:' settings. Test latest 2.x release, earliest 3.x release supported by bionic (3.6), last two production 3.x releases and nightly to cut down on cost of testing. Also run tests in 3.x series in reverse order so 3.9 runs first. Hence we fail early as newest pythons seem to have more issues with the code.

Docs
====

.. toctree::
   :maxdepth: 2

   docs/features
   docs/installation
   docs/upgrading
   docs/FAQ
   docs/user_guide
   docs/customizing
   docs/admin_guide
   docs/debugging
   docs/xmlrpc
   docs/rest
   docs/tracker_templates
   docs/glossary
   docs/acknowledgements
   docs/license
   Design Overview <docs/overview>
   Design (original) <docs/design>
   docs/developers
   Notes about the MySQL Database backend <docs/mysql>
   Notes about the PostgreSQL Database backend <docs/postgresql>
   Richard Jones implementation notes <docs/implementation>