Fixed flake8 issue as in smarie/python-genbadge#47

Author: Sylvain MARIE

ci_tools/flake8-requirements.txt

@@ -3,6 +3,7 @@ flake8>=3.6,<4
 flake8-html>=0.4,<1
 flake8-bandit>=2.1.1,<3
 bandit<1.7.3  # temporary until this is fixed https://github.com/tylerwince/flake8-bandit/issues/21
+pbr  # for bandit 1.7.2 to run
 flake8-bugbear>=20.1.0,<21.0.0
 flake8-docstrings>=1.5,<2
 flake8-print>=3.1.1,<4