[REQ] [RUBY] [FARADAY] Allow middleware to be configured

[johngallagher]

Is your feature request related to a problem? Please describe.

I want to instrument all API calls from Open API so I can measure performance.

Describe the solution you'd like

• When the generator is using Ruby with the Faraday library, I'd like the generated code to allow configuration of middleware
• It could be as simple as config.use_middlewares: [:instrumentation]
• Then I could plug in the instrumentation middleware and Faraday does the rest
• This would allow any middleware to be used and maximise the power of Faraday

Describe alternatives you've considered

• Overriding the templates - this is messy and means that any changes in the templates will need to be merged into the instrumentation changes
• Somehow inserting middleware before Faraday is initialized. This isn't currently possible
• This solution is the most flexible - the config option would only be generated if using the Faraday library and would mean we get maximum flexibility

[ekohl]

Shouldn't this be closed now that #10495 has been merged?