Test: Fixed issue with virtualenv raising AttributeError during insta…

…lltest on py34

Details:

* virtualenv raised AttributeError: 'Path' object has no attribute 'write_bytes'
  during 'make installtest' on Python 3.4 since a few days.
  This had already been reported as pypa/virtualenv#1963.
  This change fixes that by excluding virtualenv 20.0.32.
  To avoid an earlier issue where virtualenv did not install pop on Python 3.4,
  virtualenv 20.0.19 was also excluded.

Signed-off-by: Andreas Maier <andreas.r.maier@gmx.de>

new_{{ cookiecutter.github_repo }}/test-requirements.txt

@@ -24,7 +24,9 @@ yagot>=0.5.0
 # Install test direct dependencies:
 
 # virtualenv
-virtualenv>=14.0.0; python_version < '3.5'
+# Virtualenv 20.0.19 has an issue where it does not install pip on Python 3.4.
+# Virtualenv 20.0.32 has an issue where it raises AttributeError on Python 3.4.
+virtualenv>=14.0.0,!=20.0.19,!=20.0.32; python_version < '3.5'
 virtualenv>=16.1.0; python_version >= '3.5' and python_version < '3.8'
 virtualenv>=20.0.0; python_version >= '3.8'