Adding a new shipping method causes 500 error when this module is installed

[mattwebdev]

when trying to add a new shipping method and Fedex is installed i get a 500 error & this message in the drupal logs:

TypeError: Argument 2 passed to Drupal\Component\Plugin\PluginManagerBase::createInstance() must be of the type array, null given, called in .../modules/contrib/commerce/src/Plugin/Field/FieldType/PluginItem.php on line 131

[mattwebdev]

looks like the issue is that FedExPluginManager does not createInstance method, and therefore uses
PluginManagerBase::createInstance() which requires a $configuration array that is not being defined.