Fix tox issues

Author: apragacz

tox.ini

@@ -1,4 +1,6 @@
 [tox]
+requires =
+    virtualenv<20.22.0
 envlist =
     py{36}-django{20,21,22},
     py{36,37}-django{30,31,32},
@@ -11,7 +13,10 @@ allowlist_externals =
     make
 setenv =
     PYTHONPATH={toxinidir}
-commands = make test ARGS="-v --cov --cov-report xml"
+commands =
+    python -V
+    pip freeze
+    make test ARGS="-v --cov --cov-report xml"
 envdir = {toxworkdir}/venv/{envname}
 deps =
     django20: Django>=2.0,<2.1