chore: Add third example for multi-provider

[hobbsh]

Description

This PR adds another example for multi-provider configuration when calling this module with for_each. I commented the example because pre-commit broke due to this needing to be implemented slightly differently than the others.

Motivation and Context

In response to https://github.com/terraform-aws-modules/terraform-aws-acm/issues/146

Breaking Changes

None

How Has This Been Tested?

• [X] I have updated at least one of the examples/* to demonstrate and validate my change(s)
• [X] I have tested and validated these changes using one or more of the provided examples/* projects
• [X] I have executed pre-commit run -a on my pull request

[hobbsh]

@antonbabenko This method does not work without modifications to the module to support multiple provider configurations. Your comment in #146 led me to believe you don't want to support multiple provider configurations so I thought this was going to just be a way to document the workaround. If that's not the way forward, that's ok.

[github-actions[bot]]

This PR has been automatically marked as stale because it has been open 30 days with no activity. Remove stale label or comment or this PR will be closed in 10 days

[github-actions[bot]]

This PR was automatically closed because of stale in 10 days

[github-actions[bot]]

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