Update README

Author: peter-evans

README.md

@@ -60,8 +60,8 @@ This action also features [advanced configuration](docs/advanced-configuration.m
 
 | Input | Description | Default |
 | --- | --- | --- |
-| `token` | (**required**) A `repo` scoped [PAT](https://help.github.com/en/github/authenticating-to-github/creating-a-personal-access-token-for-the-command-line). | |
-| `reaction-token` | `GITHUB_TOKEN` or a `repo` scoped [PAT](https://help.github.com/en/github/authenticating-to-github/creating-a-personal-access-token-for-the-command-line). | |
+| `token` | (**required**) A `repo` scoped [PAT](https://help.github.com/en/github/authenticating-to-github/creating-a-personal-access-token-for-the-command-line). Note: `GITHUB_TOKEN` *does not* work here. | |
+| `reaction-token` | `GITHUB_TOKEN` or a `repo` scoped [PAT](https://help.github.com/en/github/authenticating-to-github/creating-a-personal-access-token-for-the-command-line). | Value of input `token` |
 | `reactions` | Add reactions. :eyes: = seen, :rocket: = dispatched | `true` |
 | `commands` | (**required**) A comma separated list of commands. | |
 | `permission` | The repository permission level required by the user to dispatch commands. (`none`, `read`, `write`, `admin`) | `write` |