fix: generate local mise.toml config when tf/tofu_version inputs are set

[Tensho]

Description

The current mise.toml config file presence check doesn't look up to the repository root:

# infrastructure estate repo
path
└─to
  └─unit               <=== when working directory is set here
    └─ terragrunt.hcl
mise.toml              <=== shell check can't find it within the scope of the unit directory

Hence, error like this come up:

I guess there was an assumption that action should always target repo root, not a unit folder. In contrast, mise looks up config file hierarchically, which is expected behaviour for those who rely on this dev tool. This PR preserves tf_version/tofu_version action inputs precedence over mise.toml, but with mise-native approach:

1. If tf_version/tofu_version input variable is set, no matter of mise.toml config file presence (at any level) – generate local mise.toml config file and let mise look it up and use.
2. If tf_version/tofu_version input variable is not set, but mise.toml config files is present (not necessary at the root, anywhere upwards the current working directory) – let mise look it up and use.
3. If tf_version/tofu_version input variable is not set and mise.toml config files is present – let mise install the latest version.

This behaviour is intuitive in terms of tool versions resolution.

Release Notes (draft)

Added

`tf_version` action input to specify Terraform version

Updated

Handle `mise.toml` config file at any level (not only at root) with mise native hierarchical lookup

Migration Guide

N/A

Notes

• Added tf_version action input to specify desired Terraform version. I don't know why it has been removed in v3, TBH. Happy to yank it if you want to preserve tofu_version + tf_path interface exclusively.
• Updates jdx/mise-action from v2 to v3. There are no breaking changes.
• Replaced MISE_GITHUB_TOKEN environment variable with github_token action input as the former one is not supported (code search)

P.S. I like the tools versioning shift towards mise and I appreciate there is an option for it 👍