Readme update for new feature

Signed-off-by: Timothy Clarke <[email protected]>

Author: timothyclarke

README.md

@@ -72,6 +72,7 @@ jobs:
 | git-push-sign-off | If true it will sign-off commit | `false` | false |
 | git-push-user-email | If empty the no-reply email of the GitHub Actions bot will be used (i.e. `github-actions[bot]@users.noreply.github.com`) | `""` | false |
 | git-push-user-name | If empty the name of the GitHub Actions bot will be used (i.e. `github-actions[bot]`) | `""` | false |
+| git-sub-dir | Name of subdirectory if if checkout `path` option is used (i.e. `modules`) | `""` | false |
 | indention | Indention level of Markdown sections [1, 2, 3, 4, 5] | `2` | false |
 | output-file | File in module directory where the docs should be placed | `README.md` | false |
 | output-format | terraform-docs format to generate content (see [all formats](https://github.com/terraform-docs/terraform-docs/blob/master/docs/FORMATS\_GUIDE.md)) (ignored if `config-file` is set) | `markdown table` | false |