Update external-repo-token requirements

README.md

@@ -115,7 +115,7 @@ You can use an external configuration file to specify the settings for this acti
 | Option                | Usage                                                                                                                                                                                    | Possible values                                                                                                                |
 |-----------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------|
 | `config-file`         | A path to a file in the current repository or an external repository. Use this syntax for external files: `OWNER/REPOSITORY/FILENAME@BRANCH`                                             | **Local file**: `./.github/dependency-review-config.yml` <br> **External repo**: `github/octorepo/dependency-review-config.yml@main` |
-| `external-repo-token` | Specifies a token for fetching the configuration file if the file resides in a private external repository. Create a token in [developer settings](https://github.com/settings/tokens). | Any token with `read` permissions to the repository hosting the config file.                                                   |
+| `external-repo-token` | Specifies a token for fetching the configuration file. It is required if the file resides in a private external repository and for all GitHub Enterprise Server repositories. Create a token in [developer settings](https://github.com/settings/tokens). | Any token with `read` permissions to the repository hosting the config file.                                                   |
 
 #### Example