add cloudwatch_log_group_class config @peter-novata (#229)
what
- Add configuration option for the cloudwatch log infrequent access
why
terraform AWS provider added support for the recent cloudwatch log infrequent access feature which reduces cloudwatch log costs by up to 50%
references
https://registry.terraform.io/providers/hashicorp/aws/latest/docs/resources/cloudwatch_log_group.html#log_group_class
https://aws.amazon.com/blogs/aws/new-amazon-cloudwatch-log-class-for-infrequent-access-logs-at-a-reduced-price/