AWS Glue CSV output has no extension

I have a Glue Job that does some ETL, I need to write the result in a CSV in a S3 bucket, here is the method I use to write :

glueContext.write_dynamic_frame.from_options(
    frame = dyf,
    connection_type = "s3",
    connection_options = {
        "path" : "path"
    },
    format = "csv",
    format_options = {
        "separator" : ",",
        "quoteChar" : -1
    }
)

It is working and I have a result but the result file has no extension.

What am I missing?

Thanks !