The pre-commit Docker image has the Hashicorp repo which makes
installing the latest version Terraform much easier.

Repeatable builds, except for variations in dependencies.

it's the default before_script action, but it would only affect the
pre-commit job (all of the others have their own before_script). It
would allow me to not skip the terraform pre-commit checks.

The pre-commit template now runs in .pre. Reorder the other jobs.