Added click module to requirements.txt file (#59)

It's used in `tests/fixtures.py` file: ``` from click.testing import CliRunner ``` Check also Travis build: https://travis-ci.org/theskumar/python-dotenv/jobs/236861670
theskumar · Aug 8, 2017 · 77dc37d · 77dc37d
1 parent e5d68ff
commit 77dc37d
Showing 1 changed file with 1 addition and 0 deletions.
diff --git a/requirements.txt b/requirements.txt
@@ -5,3 +5,4 @@ bumpversion
 wheel
 pytest-cov
 pytest-flake8
+click