Django-pandas

Fix several deprecation warnings in pandas 2.1 which became actual errors in 2.2
as per `158`_ thanks to bixbyr

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The main feature of this is release in the use of a GHA to
automate the publishing of the package to PYPI as per PR `146`_
(again much thanks graingert). Several other minor issues have also
been addressed.

.. _`146`: https://github.com/chrisdev/django-pandas/pull/146

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This version added support for Pandas >=1.3 (thanks to graingert)

Other Changes:

* Migrated from Travis to Github Actions for CI (also graingert)

* Avoid the use of deprecated methods `139`_ and `142`_ (again much thanks graingert)

* Fix for issue `135`_ (Thanks Yonimdo)

* Silence Django 3.2 errors on testing on etc. `133`_ thanks whyscream.

.. _`139`: https://github.com/chrisdev/django-pandas/issues/135
.. _`142`: https://github.com/chrisdev/django-pandas/issues/142
.. _`135`: https://github.com/chrisdev/django-pandas/issues/135
.. _`133`: https://github.com/chrisdev/django-pandas/issues/133

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Bumped version number as the previous release was incorrectly uploaded
to pypi