Add Ability to Change the Fixed "123" Example For securitySchemes API Keys

[kentbulza]

I thought there was already a request on this, but now I can't find it.

Stoplight automatically creates a fixed Example: for API keys described in securitySchemes. It would be improper for you to read example(s) from the OpenAPI JSON because the spec does not (yet) support examples in securitySchemes. HOWEVER, since Stoplight creates one with the fixed text 123 (see attached), users should be able to override it with something more representational. Can an x-api-key-example be added?