Update openAPI-3-schema.YAML

[mjbonifa]

The openAPI yaml does not parse the swagger editor (https://editor.swagger.io/) and throws the following error

Parser error 
bad indentation of a mapping entry
Jump to line 15

The description tag had the wrong indentiation

servers:
- url: http://localhost:8089/system-modeller
    description: Local server

and has been corrected

servers:
- url: http://localhost:8089/system-modeller
  description: Local server

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[kenmeacham]

I've checked this in Swagger Editor and confrimed that it fixes the issue.

I suppose we don't view this in the editor too often, as the file is (mostly) autogenerated, and looks fine when launched from the browser via System Modeller.

Thanks for fixing!