feat: Add support for list of attributes with the same key

[dougkirkley]

Pull Request Template

Description

Adds support for multiple values for a user attribute as well as backwards compatibility with the old string value

Fixes #194

Type of change

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Enhancement (non-breaking change which improves an existing feature or documentation)
• Breaking change (fix or feature that would cause existing functionality not to work as expected)

How Has This Been Tested?

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce.

Checklist:

• I have performed a self-review of my code
• I have commented on my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Pull Request contains one commit. I squash my commits.

[zmotso]

Thanks for this improvement. Please fix the comments, and we can proceed with merging.

[dougkirkley]

@zmotso This unfortunately stopped working now that I tried to update it, the k8s API isn't accepting both the string and slice values. If you have any ideas as to why that is happening now, let me know!

[zmotso]

Please check #205 (comment)

[dougkirkley]

@zmotso @MykolaMarusenko Do you think we can make a new release once this PR is merged in?