v8.0.0: OpenTofu Support, Format and Validate

Highlights

• Implemented OpenTofu GitHub Action to deliver first-class support for tofu, while maintaining backwards-compatibility with terraform.
• Optional TF fmt and validate steps available by default.

Added

• TVP_CLI_USES=tofu or TVP_CLI_USES=terraform for users to choose between opentofu/setup-opentofu or hashicorp/setup-terraform.
• TVP_FMT_ENABLE and TVP_VALIDATE_ENABLE to toggle TF fmt and validate commands, respectively.
• Diff of TF fmt command as a separate collapsible section in the PR comment.
• paths: ['**/*.tf*'] to on: pull_request so that the workflow is only triggered when a PR contains changes to Terraform files.
• TVP_BACKEND_CONFIG_FROM_WORKSPACE, TVP_BACKEND_CONFIG_PREFIX, and TVP_BACKEND_CONFIG_SUFFIX for consistency with TVP_VAR_FILE_ counterparts.

Changed

• References to "TF" from "Terraform", to be vendor-neutral with HashiCorp's and OpenTofu's offerings.
• PR labels prefix from terraform: to tf:, and change colour depending on tofu (#FFDA18) or terraform (#5C4EE5) usage.
• Documentation to reflect changes to inputs.

Deprecated

• CONFIG_TF_ prefixed variables to TVP_ prefix instead, to be consistent with Terraform/OpenTofu-Via-PR (TVP).

Secured

• Version support v8.0.0 and above.
• peter-evans/find-comment dependency by replacing with actions/github-script.
• xt0rted/pull-request-comment-branch dependency by replacing with actions/github-script.
• myrotvorets/set-commit-status-action dependency by replacing with actions/github-script.

Commits changelog: v7.1.0...v8.0.0