Add Support for Ignoring Changes to update_time in google_artifact_registry_repository resource

[oerd]

First, thank you for maintaining this Terraform module. It's been very helpful for managing our GCP infrastructure.

Issue Summary:

We've encountered an issue related to the update_time attribute of the google_artifact_registry_repository resource when using this module to manage Google Artifact Registry repositories. Specifically, whenever we push Docker images to the Artifact Registry outside of Terraform (e.g., via CI/CD pipelines), the update_time attribute gets updated. This causes Terraform to detect changes made outside of its management and results in warnings during terraform plan or terraform apply operations.

Detailed Explanation:

Here's the warning we receive:

Note: Objects have changed outside of Terraform

Terraform detected the following changes made outside of Terraform since the last "terraform apply" which may have affected this plan:

  # module.artifact_registry.google_artifact_registry_repository.repo has changed
  ~ resource "google_artifact_registry_repository" "repo" {
        id                     = "projects/our-project-stage/locations/europe-west3/repositories/our-project-stage"
        name                   = "our-project-stage"
      ~ update_time            = "2024-11-25T15:25:53.371764Z" -> "2024-11-26T14:15:49.657338Z"
        # (other attributes omitted)
    }

Unless you have made equivalent changes to your configuration, or ignored the relevant attributes using ignore_changes, the following plan may include actions to undo or respond to these changes.

This warning occurs because the update_time attribute changes whenever the repository is modified, including when new images are pushed. Since we cannot modify the module's code to add a lifecycle block that ignores changes to this attribute, we're unable to suppress these warnings.