Add group_vars directory

Without this directory, Molecule would fail with an error:

    CRITICAL The source path '/home/zuul/src/github.com/openstack-k8s-operators/edpm-ansible/roles/edpm_kernel/molecule/default/../../../../group_vars/' does not exist.
    WARNING  An error occurred during the test sequence action: 'prepare'. Cleaning up.
    CRITICAL The source path '/home/zuul/src/github.com/openstack-k8s-operators/edpm-ansible/roles/edpm_kernel/molecule/default/../../../../group_vars/' does not exist.

Signed-off-by: Daniel Pawlik <[email protected]>

Author: danpawlik

group_vars/README.md

@@ -0,0 +1 @@
+# File was created to satisfy molecule test requirement to get "group_vars" dir.