prototypes: xci: Add 'ansible-hardening' role to the requirements file

prototypes: xci: Add 'ansible-hardening' role to the requirements file

Upstream commit 2798cf403c47d165cd8d34d7888990dce1f827f8 ("Use new
ansible-hardening role") added the new 'ansible-hardening' role to the
ansible-role-requirements.yml file and as such we also need to take that
into consideration. The sha hash does not matter much at this point
since it will be fixed the next time we tag all the roles.

Change-Id: I5444af948e2b83de49863e7e28f3918fed88c90d
Signed-off-by: Markos Chandras <mchandras@suse.de>