**Description:** [actions/setup-node](https://github.com/actions/setup-node), [actions/setup-python](https://github.com/actions/setup-python), [ruby/setup-ruby](https://github.com/ruby/setup-ruby), and [erlef/setup-beam](https://github.com/erlef/setup-beam) all support reading from [`.tool-versions`](https://asdf-vm.com/guide/introduction.html). It would be helpful to have such support consistently in all official setup actions. **Justification:** With over 18k stars and [over 400 plugins](https://github.com/topics/asdf-plugin), [asdf](https://github.com/asdf-vm/asdf) is the most popular multi-language runtime manager. `.tool-versions` is becoming the de facto standard for pinning runtimes, package managers, and other development tools as most other standardized file formats support only one tool. **Are you willing to submit a PR?** No