terraform-lambda-sfn: Update runtime and Powertools to python3.12

[kakakakakku]

Issue #, if available:
N/A

Description of changes:
Hi😀 Thanks for the useful patterns!

To prevent future deployment issues, I updated the Lambda Python runtime and Powertools version to python3.12.

While testing terraform-lambda-sfn, I noticed that the Lambda runtime version python3.8 was deprecated. Although it's still deployable at the moment, it will not be allowed after October 1, 2025.
https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html

Check

terraform apply completed successfully and works good.

Warning

Warning is likely caused by the fact that the AWS provider version is currently at v6 (due to >= 4.9 constraint), and data.aws_region.current.name is now a deprecated attribute. There is no functional impact at this time👍

$ terraform apply

╷
│ Warning: Deprecated attribute
│ 
│   on .terraform/modules/lambda_function/outputs.tf line 9, in output "lambda_function_arn_static":
│    9:   value       = local.create && var.create_function && !var.create_layer ? "arn:aws:lambda:${data.aws_region.current.name}:${data.aws_caller_identity.current.account_id}:function:${var.function_name}" : ""
│ 
│ The attribute "name" is deprecated. Refer to the provider documentation for details.
│ 
│ (and one more similar warning elsewhere)
╵

Apply complete! Resources: 20 added, 0 changed, 0 destroyed.

Thank you😀

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[kakakakakku]

note: https://docs.powertools.aws.dev/lambda/python/latest/#lambda-layer

[kakakakakku]

note: https://registry.terraform.io/providers/hashicorp/aws/latest/docs/data-sources/region

name - (Optional, Deprecated) Full name of the region to select. Use region instead.

╷
│ Warning: Deprecated attribute
│ 
│   on main.tf line 107, in module "lambda_function":
│  107:   layers = ["arn:aws:lambda:${data.aws_region.current.name}:017000801446:layer:AWSLambdaPowertoolsPythonV3-python312-x86_64:19"]
│ 
│ The attribute "name" is deprecated. Refer to the provider documentation for details.
│ 
│ (and 5 more similar warnings elsewhere)
╵