Show how the plan is applied (terraform apply -auto-approve)

In the https://github.com/hashicorp/setup-terraform/blob/main/README.md, I think you have an example that creates the tfplan.txt on pull request.

Now on a merge, aka a push to main, why don't you have an example to pick up that **tfplan.txt**, for `terraform apply -auto-approve`. Or is expected the whole plan is run from scratch on a push to main??