fix: remove source_code_hash and close artifact-packager ref issue (#8)

Remove the source_code_hash argument from aws_lambda_function.this to
prevent terraform plan failures when the artifact zip does not yet exist
(e.g. CI environments without Docker). The filename attribute alone is
sufficient — Terraform detects content changes at apply time.

The artifact-packager ref was already updated to v1.4.1 in a prior
commit, which resolved the forced-rebuild race condition.

Closes #4
Closes #6

Author: sgtoj

main.tf

@@ -98,8 +98,7 @@ resource "aws_lambda_function" "this" {
   reserved_concurrent_executions = var.lambda_config.reserved_concurrent_executions
   architectures                  = [var.lambda_config.architecture]
 
-  filename         = module.bot_artifact[0].artifact_package_path
-  source_code_hash = filebase64sha256(module.bot_artifact[0].artifact_package_path)
+  filename = module.bot_artifact[0].artifact_package_path
 
   environment {
     variables = local.lambda_environment