Feature request: Support --use-previous-template flag

[chrisburch-govos]

CloudFormation provides the --use-previous-template flag when updating stacks and creating change sets. This is useful when performing updates against stacks with templates that are too large to feed directly via JSON (due to the character limit). Currently, this action does not implement that flag.

[kddejong]

Thanks for the feature request. Just wanted to note that this action already supports S3 URLs as the template input, which handles the template body size limit (51,200 bytes). For example:

- uses: aws-actions/aws-cloudformation-github-deploy@v2.0.0
  with:
    name: MyStack
    template: https://s3.amazonaws.com/my-bucket/my-template.yaml

Is there a specific use case where --use-previous-template would be needed beyond working around the size limit? For instance, are you looking to update only parameters/tags without re-specifying the template?