feat: add subscription_tags_ignored variable

[JPEasier]

Overview/summary

This PR adds the subscription_tags_ignored variable to the subscription module. This variable allows users to specify a list of tags to ignore when updating the subscription.

In one customer scenario, the customer has internal cost center information that is applied and updated as tags to the subscription outside of the vending module. Running the Terraform deployment results in overwriting the tags, so we need the ability to ignore certain tags.

Testing evidence

Please provide testing evidence to show that your Pull Request works/fixes as described and documented above.

As part of this pull request I have

• Checked for duplicate Pull Requests
• Associated it with relevant issues, for tracking and closure.
• Run and make fmt & make docs to format your code and update documentation.
• Created unit and deployment tests and provided evidence.
• Updated relevant and associated documentation.

[matt-FFFFFF]

@JPEasier

Have you tested that this works?

I believe that lifecycle.ignore_chanegs cannot reference a variable. I tested this locally to be sure:

❯  t plan
╷
│ Error: Invalid expression
│ 
│   on main.tf line 9, in resource "terraform_data" "test":
│    9:     ignore_changes = var.ignore_changes
│ 
│ A static list expression is required.
╵

[JPEasier]

Hi @matt-FFFFFF,
Nope, I haven't tested it jet, our current solution is to load the module locally and manipulate the subscription submodule.

Anyway, I found this open issue hashicorp/terraform#24188
So currently there is no chance for a dynamic lifecycle element.

So we can close this PR, but I am open for ideas! 😄