To read environment variables while using client generated by open-api-generator

[p172913]

Summary

This pull request adds support for to read and use environment variables while using kubernetes client generated by open-api-generator

Validation

• Ran ./mvnw clean package successfully.
  
• Created configuration.py used in kubernetes using modules/openapi-generator-cli/target/openapi-generator-cli.jar
  

[p172913]

@openapitools/generator-core-maintainers could you take a look at this?

[p172913]

@canadaduane , @jqr , @wpiekutowski , @farcaller please take a look at my PR...

[wing328]

please follow step 3 to update the samples

[wing328]

can you explain this part about cliOptions?

[p172913]

This will assign variable with None value if we didn't provide any value to it...

[wing328]

btw, you can use customized templates (e.g.-t via CLI) to customize the mustache templates updated by this PR

[wing328]

just so we're on the same page, which version of openapi generator did kubernetes python client use to generate the client?

[p172913]

As per change logs we are using v4.3.0

[wing328]

the python client generator has been completely refactored in openapi generator v7.0.0 (to support only python 3.x) so i don't think the chnage you made here will propagate to the kubernetes python client repo.

still you can use customized templates with the changes you applied in this pr