* add `workflow_dispatch`
* Add an environment variable to indicate which repository the currently running Action came from.
* Expose the Action ref as well.
* Move setting `github.action_repository` and `github.action_ref` to `ActionRunner.cs`.
* Don't set `action_repository` and `action_ref` for local Actions.
Co-authored-by: Tingluo Huang <[email protected]>
