Add bandit target to shipyard

This patch set adds [testenv:bandit] target to the shipyard project
to allow CICD to perform necessary static code analysis on the
shipyard project.

Change-Id: I748c52bc90ce667c891f15d018df2c01ea9ec351

test-requirements.txt

@@ -7,3 +7,6 @@ psycopg2==2.7.3
 
 # Linting
 flake8==3.3.0
+
+# Security scanning
+bandit>=1.1.0 # Apache-2.0

tox.ini

@@ -13,6 +13,9 @@ commands=
 [testenv:pep8]
 commands = flake8 {posargs}
 
+[testenv:bandit]
+commands = bandit -r shipyard_airflow -x tests -n 5
+
 [flake8]
 # NOTE(Bryan Strassner) ignoring F841 because of the airflow example pattern
 #     of naming variables even if they aren't used for DAGs and Operators.