pass the PROGRAMDATA environment variable when invoking fix-lint (tox-dev#709)

This fixes `error setting certificate verify locations` errors when cloning a git repo using git for Windows.

Author: jurko-gospodnetic

tox.ini

@@ -28,6 +28,9 @@ commands = sphinx-build -d {toxworkdir}/docs_doctree doc {toxworkdir}/docs_out -
 basepython = python3.6
 passenv = {[testenv]passenv}
  HOMEPATH
+ # without PROGRAMDATA cloning using git for Windows will fail with an
+ # `error setting certificate verify locations` error
+ PROGRAMDATA
 extras = lint
 description = run static analysis and style check using flake8
 commands = python -m flake8 --show-source tox setup.py {posargs}