Keep test dependencies as-is for now

These are leading to multiple failures:

- flake8 fails with various issues
- isort fails with various issues
- pytest fails on a couple of 2FA tests

While we can and should upgrade these dependencies, the priority is
fixing the build so that we can do this reliably.

requirements_for_test.txt

@@ -1,14 +1,14 @@
 -r requirements.txt
-isort==5.7.0
+isort==4.3.21
-pytest==6.2.2
+pytest==5.3.2
 pytest-env==0.6.2
-pytest-mock==3.5.1
+pytest-mock==1.11.2
-pytest-xdist==2.2.1
+pytest-xdist==1.31.0
-beautifulsoup4==4.9.3
+beautifulsoup4==4.8.1
-freezegun==1.1.0
+freezegun==0.3.12
-flake8==3.8.4
+flake8==3.7.9
-flake8-bugbear==20.11.1
+flake8-bugbear==19.8.0
-flake8-print==4.0.0
+flake8-print==3.1.4
-requests-mock==1.8.0
+requests-mock==1.7.0
 # used for creating manifest file locally
 jinja2-cli[yaml]==0.7.0