[#3809] change email from ckan-dsicuss to ckan-users in Support section

[tino097]

Fixes #
#3809

Proposed fixes:

changed email link, from ckan-discuss to ckan-users
https://lists.okfn.org/mailman/listinfo/ckan-users

Features:

• includes tests covering changes
• includes updated documentation
• includes user-visible changes
• includes API changes
• includes bugfix for possible backport

Please [X] all the boxes above that apply

[amercader]

@tino097 please use this text that matches what's on https://ckan.org/community/

Support
-------
For general discussion around CKAN, you can write to the `Google Group`_.

If you need help with CKAN and and want to ask a or want to ask a question about CKAN, use either the
`ckan-dev`_ mailing list or the `CKAN tag on Stack Overflow`_ (try
searching the Stack Overflow and ckan-dev `archives`_ for an answer to your
question first).

If you've found a bug in CKAN, open a new issue on CKAN's `GitHub Issues`_ (try
searching first to see if there's already an issue for your bug).

If you find a potential security vulnerability please email security@ckan.org,
rather than creating a public issue on GitHub.

.. _Google Group: https://groups.google.com/forum/#!forum/ckan-global-user-group
.. _CKAN tag on Stack Overflow: http://stackoverflow.com/questions/tagged/ckan
.. _ckan-dev: https://lists.okfn.org/mailman/listinfo/ckan-dev
.. _archives: https://www.google.com/search?q=%22%5Bckan-dev%5D%22+site%3Alists.okfn.org.
.. _GitHub Issues: https://github.com/ckan/ckan/issues