docs: add option to readme

README.md

@@ -81,6 +81,7 @@ Refer to the [GitHub Actions recipe for npm package provenance](https://semantic
 | `npmPublish` | Whether to publish the `npm` package to the registry. If `false` the `package.json` version will still be updated. | `false` if the `package.json` [private](https://docs.npmjs.com/files/package.json#private) property is `true`, `true` otherwise. |
 | `pkgRoot`    | Directory path to publish.                                                                                         | `.`                                                                                                                              |
 | `tarballDir` | Directory path in which to write the package tarball. If `false` the tarball is not be kept on the file system.    | `false`                                                                                                                          |
+| `packageManager` | Package manager used to publish the package (`npm` and `pnpm` are supported).    | `npm`                                                                                                                          |
 
 **Note**: The `pkgRoot` directory must contain a `package.json`. The version will be updated only in the `package.json` and `npm-shrinkwrap.json` within the `pkgRoot` directory.