We have added Ubuntu 18.04 support for the behave CLI tests.
Co-authored-by: NJacob Champion <pchampion@pivotal.io>
Co-authored-by: NDavid Krieger <dkrieger@pivotal.io>
Co-authored-by: NNikolaos Kalampalikis <nkalampalikis@pivotal.io>

(cherry picked from commit 35d74d57)