Replace 'ec2_facts' with 'ec2_metadata_facts' to fix a deprecation warning

[Rylon]

Description of PR
Just a one-line change to fix the following deprecation warning:

[DEPRECATION WARNING]: ec2_facts is kept for backwards compatibility but usage is discouraged. The module
 documentation details page may explain more about this rationale.. This feature will be removed in a
future release. Deprecation warnings can be disabled by setting deprecation_warnings=False in
ansible.cfg.

It seems like ec2_metadata_facts is a drop-in replacement for ec2_facts. It was added in Ansible 2.4, which is the minimum version you support with this role, so I think it should be ok?

Thanks!

Type of change
Bugfix Pull Request

[dj-wasabi]

Thanks! 👍