Revert pytest-cov

currently still need to support 3.8

Author: sliverc

requirements/requirements-testing.txt

@@ -1,7 +1,7 @@
 factory-boy==3.3.1
 Faker==33.0.0
 pytest==8.3.3
-pytest-cov==6.0.0
+pytest-cov==5.0.0
 pytest-django==4.9.0
 pytest-factoryboy==2.7.0
 syrupy==4.7.2