I would like to deploy a SAM application to localstack.
I execute the command

aws cloudformation package \
    --output-template-file packaged.yml \
    --endpoint-url http://localhost:4581 \ 
    --profile localstack \
    --s3-bucket my-bucket \
    --template-file template.yaml

but get

Unable to upload artifact XXX referenced by CodeUri parameter of XXX resource.
An error occurred (InvalidAccessKeyId) when calling the PutObject operation: The AWS Access Key Id you provided does not exist in our records.

because it requests real S3 instead of using the local one.

I need an additional option like --s3-endpoint-url to solve this issue.

There is #3309 PR, but it was not checked for a year.
See also localstack/localstack#1783