List type configuration cannot be overridden

[KosukeOkamoto]

Describe the bug

Oper8 have config.yaml for default configuration and environment variable can override them. However, list type configuration can not be overridden since aconfig ignore them. Some important configuration, especially supported_versions, are currently not configurable.

Platform

Please provide details about the environment you are using, including the following:

• Interpreter version: Any
• Library version: Any

Sample Code

Please include a minimal sample of the code that will (if possible) reproduce the bug in isolation

Expected behavior

List type configurations are configurable.

Observed behavior

List type configurations are always default value.

Additional context

I think the best solution is to allow overriding configurations with a provided config file. Or can we accept list type environment variable somehow?