Stop using deprecated template_file (use templatefile instead)

[npwolf]

When running on my M1 Mac, I was getting the following error:

│ Error: Incompatible provider version
│
│ Provider registry.terraform.io/hashicorp/template v2.2.0 does not have a package available for your current platform, darwin_arm64.
│
│ Provider releases are separate from Terraform CLI releases, so not all providers are available for all platforms. Other versions of
│ this provider may have different platforms supported.

This PR stops the error by moving away from the deprecated template_file to templatefile.