feat: Enable allowUnfree for Terraform versions >= 1.6

[sestrella]

Related with #71

TODO

• Add breaking change note to commit message
• Update the configuration input once it gets merged into main

[oscar-izval]

Hey @sestrella, this is looking great! I like it a lot. I wonder if we should create a ./template/config instead of using ./config as the template. That way we could also provide a full example for those wanting to go that route (and possibly fix the current issue, because it's missing a devshell for that simple flake).

[sestrella]

@oscar-izval I addressed your comment. Would you mind taking a second look? In terms of how to release this change, I believe we would need to merge it first with the config input pointing to this feature branch, and then once the config template is on main, we could update the input and flake.lock file before doing a new release. What do you think?

[oscar-izval]

LGTM!