fix: use relative path as lambda function local package path

[b6pzeusbc54tvhw5jgpyw8pwz2x6gs]

To avoid unintentional state changes when working in multiple environments,
Use relative path as lambda function local package path.

Before:

  # module.next_image_optimizer.module.image_optimizer.aws_lambda_function.this[0] will be created
  + resource "aws_lambda_function" "this" {
      ...
      + filename                       = "/Users/aluc/projects/terraform-aws-next-js-image-optimization/examples/with-existing-cloudfront/.terraform/modules/next_image_optimizer.lambda_content/download/@millihq/tf-next-image-optimization/dist.zip"
      ...

As seen in Before, if the filename is set to an absolute path, the username is included, and the lambda function is updated even if it is the same source in another user's environment.

After:

  # module.next_image_optimizer.module.image_optimizer.aws_lambda_function.this[0] will be created
  + resource "aws_lambda_function" "this" {
      ...
      + filename                       = ".terraform/modules/next_image_optimizer.lambda_content/download/@millihq/tf-next-image-optimization/dist.zip"
      ...

In After, setting the relative path based on cwd, update is attempted only when the actual source code is changed.

PR of other related projects:

• chore: add rel_path output for relative path terraform-npm-download#6

[ofhouse]

LGTM 👍