Update python dependencies (#733)

* Test against Django 5.1

* Remove testing new versions of Django with old versions of postgres

* Add a shim for QuerySetEqual to support both Django 3.2 and Django 5.1

* Update Python Pygments package to 2.18.0

* Update Python coverage package to 7.6.1

* Update Python freezegun package to 1.5.1

* Update Python pytest-cov package to 5.0.0

* Update Python pytest-django package to 4.8.0

requirements.txt

@@ -1,8 +1,8 @@
-coverage==7.4.0
+coverage==7.6.1
 factory-boy==3.3.0
-freezegun==1.4.0
+freezegun==1.5.1
 networkx==2.6
 pydot==1.4.2
-pygments==2.17.2
-pytest-cov==4.1.0
-pytest-django==4.7.0
+pygments==2.18.0
+pytest-cov==5.0.0
+pytest-django==4.8.0