No host and schemes fields in swagger

[kazuhitoyokoi]

What are the steps to reproduce?

1. Install node-red-node-swagger on Node-RED flow editor.
2. Create REST API using http-in, template, http response nodes.
3. Import the generated swagger definition on Swagger Editor using the URL, http://localhost:1880/http-api/swagger.json .
4. Access the endpoint from the Swagger Editor.

What happens?

"404 Not Found" error occurred because the Swagger Editor access the own URL, https://editor.swagger.io/

What do you expect to happen?

The swagger definition contains host and schemes fields. And the Swagger Editor can access the endpoint on Node-RED.

Please tell us about your environment:

• [x] Node-RED version: 1.2.9
• [x] Node.js version: 10.20.1
• [x] npm version: 7.6.0
• [x] Platform/OS: macOS Big Sur 11.2.3
• [x] Browser: Google Chrome 89.0.4389.114 (Official Build) (x86_64)

[kazuhitoyokoi]

@knolleary @dceejay Could you review this pull request when you have time?

[dceejay]

HI - sorry - yes it looks good to me. Happy to merge. @knolleary ?