[Enhancement]: Add AllowEngineModeChange to aws_rds_cluster

[kiranjthomas]

Description

The AWS GO SDK supports the "modifying the engine mode of database clusters". See https://github.com/aws/aws-sdk-go/pull/4801

This option is helpful in avoiding downtime when migrating a v1 serverless cluster to provisioned. See https://docs.aws.amazon.com/AmazonRDS/latest/AuroraUserGuide/aurora-serverless.modifying.html#aurora-serverless.modifying.convert

Without this option, I believe the aws_rds_cluster would need to be destroyed and then created.

Affected Resource(s) and/or Data Source(s)

aws_rds_cluster

Potential Terraform Configuration

resource "aws_rds_cluster" "default" {
  cluster_identifier        = "aurora-cluster-demo"
  engine                    = "aurora-mysql"
  engine_version            = "5.7.mysql_aurora.2.03.2"
  availability_zones        = ["us-west-2a", "us-west-2b", "us-west-2c"]
  database_name             = "mydb"
  master_username           = "foo"
  master_password           = "bar"
  backup_retention_period   = 5
  preferred_backup_window   = "07:00-09:00"
+ allow_engine_mode_change  = true
}

References

No response

Would you like to implement a fix?

Yes

[github-actions[bot]]

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