add erb support for config_map_files and generic_secret_data helpers

[tongueroo]

This is a 🙋‍♂️ feature or enhancement.

• I've added tests (if it's a bug, feature or enhancement)
• I've adjusted the documentation (if it's a feature or enhancement)
• The test suite passes (run bundle exec rspec to verify this)

Summary

• Add ERB support for config_map_files and generic_secret_data helpers.
• Improve env-like files parsing

Context

Related #60

How to Test

Go through the examples on the docs.

• https://kubes.guru/docs/helpers/builtin/config-map-files/
• https://kubes.guru/docs/helpers/google/secret_data/
• https://kubes.guru/docs/helpers/aws/secret_data/

Version Changes

Patch