Depend at least on ansible 2.7 or greater

ansible/requirements.txt

-ansible>=2.8
+# ansible>=2.7 is needed for using the `k8s` resource
+ansible>=2.7

test/requirements.txt

-ansible>=2.8
+# ansible>=2.7 is needed for using the `k8s` resource
+ansible>=2.7
 behave-webdriver>=0.2.2
 certifi>=2019.3.9
 # Needed for ansible k8s resource
 openshift>=0.8.6
+# Needed for testinfra using the ansible module
 paramiko
 psutil>=5.5.0
 pycurl>=7.43.0.2