* Remove system check for Django version
* Closes#175
* Bump version and amend CHANGELOG
* Update with GitHub action CI
* Update README with Python and Django versions
* Limit Django version to 3.2, inclusively.
* Add note on Django constraints to README
* Bump minor version
* Justified by dropping support for dependency versions
* Drop support for Django 2.0-2.1, Python 3.5
* Change CI badge in README to GitHub actions
* Add support for Pymemcache for Django 3.2+
* Add Django 3.2 to test matrix
* Fix MySQL test_explain
* Allow filebased delta leniency in tests
* Allow Subquery in finding more Subqueries (Fixes#156)
* Reverts #157 with proper fix. The initial problem was due to `django.db.models.expressions.Subquery` allowing both QuerySet and sql.Query to be used.
* Fixes Django 3.2 test_subquery and test_invalidate_subquery testing by also checking the lhs
* Fix Django 2.2 Subquery having no query attr
* Fix filebased test time delta
* Fix test_invalidate_having due to new inner_query
* The new inner_query replaces subquery for Django 3.2 where subquery is now a boolean. That's why I initially used that TypeError in _get_tables_from_sql. inner_query looks to be a sql.Query
* Add PyMemcacheCache to supported cache backends
Co-authored-by: Dominik George <nik@naturalnet.de>
