When PUTting an S3 object to Localstack with attached Metadata, if a key contains an underscore it is replaced with a dash.

However, when the same request is performed against the real S3, the key is not modified.

Example Input:
key_with_underscores => test

Localstack Result:
key-with-underscores => test

S3 Result:
key_with_underscores => test

Localstack Version: 0.10.5

Tested using AWS v2 S3 client
if not (method == 'POST' and parsed_path.query == 'delete' and '<Delete' in to_str(data or '')):
        return
    content = to_str(response._content)
    if '<Error>' not in content:
        return
    result = xmltodict.parse(content).get('DeleteResult')
    errors = result.get('Error')
    errors = errors if isinstance(errors, list) else [errors]
    deleted = result.get('Deleted')
    if not isinstance(result.get('Deleted'), list):
        deleted = result['Deleted'] = [deleted] if deleted else []
    for entry in list(errors):
        if set(entry.keys()) == set(['Key']):
            errors.remove(entry)
            deleted.append(entry)
    if not errors:
        result.pop('Error')
    response._content = xmltodict.unparse({'DeleteResult': result})
def remove_xml_preamble(response):