feat: Add ECR Lifecycle Policy Option to docker-build module

[1Mill]

Description

Let users add ECR lifecycle policy rules to automate the cleaning up of unused images generated by the docker-build module.

Motivation and Context

I use this module to build and publish many Docker Images to ECR and I want to be able to easily delete unneeded Docker Images. Since this module is the one building and publishing the Docker Images to ECR it seems best to extend the module to also support the JSON ECR lifecycle policy document.

Breaking Changes

This is not a breaking change and is only added non-breaking functionality to the module.

How Has This Been Tested?

• I have tested and validated these changes using one or more of the provided examples/* projects

// examples/container-image/main.tf

module "docker_image" {
  source = "../../modules/docker-build"

  create_ecr_repo = true
  ecr_repo        = random_pet.this.id
  image_tag       = "1.0"
  source_path     = "context"
  build_args = {
    FOO = "bar"
  }
  ecr_repo_lifecycle_policy = <<EOF
{
  "rules": [
    {
      "rulePriority": 1,
      "description": "Keep only the last 2 images",
      "selection": {
        "tagStatus": "any",
        "countType": "imageCountMoreThan",
        "countNumber": 2
      },
      "action": {
        "type": "expire"
      }
    }
  ]
}
EOF
}

[antonbabenko]

Looks pretty good. Please fix docs (pre-commit run -a) to make GH checks green.

[1Mill]

@antonbabenko, I committed your changes about the default null value and updated the README. I gad quite a few issues with getting pre-commit working so may want to double check the pre-commit run -a command.

[antonbabenko]

This PR is included in version 2.29.0 🎉

[github-actions]

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