[REQ] Ruby - Support refreshing access tokens

[lisamburns]

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

The autogenerated ruby clients only can be configured with a static access token. This does not work well for integrations where tokens are short-lived and need to be refreshed.

Describe the solution you'd like

The ruby client would have a configuration for a proc to get the access token.
The proc could be configured to retrieve a new access token.

Describe alternatives you've considered

I could override the Configuration class to add this property, but that makes it hard to upgrade versions.

Additional context

[wing328]

@lisamburns your suggestion sounds good. can you please file a PR with the suggested enhancement when you've time? Thanks.