First of all thank you @zuzannast for this excellent plugin, very needed and easy to setup.

There is a small issue when validator_enabled is set false, it looks like it's still trying to do a validation but with an url set to null?<path_to_yaml_file>

Additionally a config option to customize the URL of validationUrl would be nice, as well as having the latest version (3.6) of SwaggerUI.

I'll try to send a PR the following week.