Enhance terraform/tofu segment version detection with tenv support

[grimm26]

Code of Conduct

• I agree to follow this project's Code of Conduct

What would you like to see changed?

The terraform segment tries to detect version from one of these files:

• main.tf
• versions.tf
• terraform.tfstate

terraform.tfstate is only applicable if you are using a local state file, which no production setup should. In my setup I don't use main.tf or versions.tf so this segment doesn't really work.

Many people use tenv to manage their terraform/tofu version and so we can check if there is a hint from tenv to detect the version. The segment could check:

• TOFUENV_TOFU_VERSION env variable
• .opentofu-version
• TFENV_TERRAFORM_VERSION env variable
• .terraform-version

Or just use tenv tofu detect and tenv terrform detect

[grimm26]

oh I also realized that tenv can be integrated as a library, too! That would be even better. https://github.com/tofuutils/tenv/blob/main/TENV_AS_LIB.md