AWS supports the following Ruby runtimes:

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Name | Identifier | SDK for Ruby | Operating system
-- | -- | -- | --
Ruby 2.7 | ruby2.7 | 3.0.1 | Amazon Linux 2
Ruby 2.5 | ruby2.5 | 3.0.1 | Amazon Linux

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Currently, `localstack/lambda` only contains the `ruby2.5` tag. Will the 2.7 runtime be supported in the (near) future?
testutil.create_lambda_function(
            handler_file=TEST_LAMBDA_ECHO_FILE,
            func_name=function_name,
            runtime=LAMBDA_RUNTIME_PYTHON36
        )
        table_arn = aws_stack.create_dynamodb_table(ddb_table, partition_key='id')['TableDescription']['TableArn']
        lambda_client = aws_stack.connect_to_service('lambda')
        rs = lambda_client.create_event_source_mapping(
            FunctionName=function_name,
            EventSourceArn=table_arn
        )
        uuid = rs['UUID']
        dynamodb = aws_stack.connect_to_resource('dynamodb')
        table = dynamodb.Table(ddb_table)
        items = [
            {'id': short_uid(), 'data': 'data1'},
            {'id': short_uid(), 'data': 'data2'}
        ]
        table.put_item(Item=items[0])
        events = get_lambda_log_events(function_name)
        
        self.assertEqual(len(events[0]['Records']), 1)
        
        lambda_client.update_event_source_mapping(UUID=uuid, Enabled=False)
        table.put_item(Item=items[1])
        events = get_lambda_log_events(function_name)
        
        self.assertEqual(len(events[0]['Records']), 1)
        
        dynamodb_client = aws_stack.connect_to_service('dynamodb')