With the new Vagrant "ansible.force_remote_user" option set to true by
default, SSH User used to connect to the VM is now set to "vagrant" into
the Ansible inventory (generated by Vagrant).
This behavior does not permit to use Ansible "remote_user" option into
playbooks (overridden by the inventory), that's the reason why the
deployment fail.
With the new Vagrant "ansible.force_remote_user" option set to true by default, SSH User used to connect to the VM is now set to "vagrant" into the Ansible inventory (generated by Vagrant). This behavior does not permit to use Ansible "remote_user" option into playbooks (overridden by the inventory), that's the reason why the deployment fail.