feat(elasticache-redis): add snapshot retention limit

[nitrocode]

what

• add snapshot retention limit

why

• Resolves ElastiCache.1 (ElastiCache (Redis OSS) clusters should have automatic backups enabled) securityhub control by giving the ability to set this value to a number greater than 0

references

• Default is 0 https://github.com/cloudposse/terraform-aws-elasticache-redis/blob/9104d9a6a120ae9c90f59c5eb4ea711cc2d2c6bb/variables.tf#L223-L227
• Module received the feature 5 years ago so no need to update the module version Enable backups terraform-aws-elasticache-redis#45
• Related PR feat(elasticache-redis): add engine input for valkey support #1170 which upgrades the module

[GabisCampana]

@Nuru