Add an environment variable to indicate which repository the currently running Action came from. (#585)

* 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 <tingluohuang@github.com>

src/Runner.Worker/GitHubContext.cs

@@ -10,6 +10,8 @@ namespace GitHub.Runner.Worker
         {
             "action",
             "action_path",
+            "action_ref",
+            "action_repository",
             "actor",
             "api_url",
             "base_ref",
@@ -55,4 +57,4 @@ namespace GitHub.Runner.Worker
             return copy;
         }
     }
-}
+}