OpenAPI paths should be relative to basePath

When using this module to rewrite paths, the OpenAPI description has invalid paths:

{
  "basePath": "/jsonapi",
  "paths": {
    "/api/recipes": ...
  }
  ...
}

If I'm reading the OpenAPI spec correctly, the paths are supposed to be concatenated to basePath. But that would result in /jsonapi/api/recipes, which is not a valid URL.

If I uninstall this module, the output is correct:

{
  "basePath": "/jsonapi",
  "paths": {
    "/node/recipe": ...
  }
  ...
}