Downgrade test requirements

For some reason this makes test to fail in the corporate site.
We should investigate the root cause, but in the meantime downgrading
works.

Author: stsewd

requirements/testing.txt

@@ -2,8 +2,8 @@
 -r local-docs-build.txt
 
 django-dynamic-fixture==2.0.0
-pytest==4.2.0
-pytest-django==3.4.7
+pytest==4.1.1
+pytest-django==3.4.5
 pytest-xdist==1.26.1
 pytest-cov==2.6.1
 apipkg==1.5