[deck] Ansible best practices: add excerpt of a requirements.yml

[nqb]

In Ansible best practices, the requirements.yml file is mentioned without its syntax.

It would be nice to add a short excerpt of this file, like for site.yml on the 31 page.

Thanks for this nice deck !

[nqb]

An example here:

https://github.com/geerlingguy/ansible-for-devops/blob/ea8ef619809ff6d60e183f8c618413919f9c2774/deployments-balancer/requirements.yml