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?
function_name = '{}-{}'.format(TEST_LAMBDA_FUNCTION_PREFIX, short_uid())
        aws_stack.create_dynamodb_table(table_name, partition_key='id')
        testutil.create_lambda_function(handler_file=TEST_LAMBDA_PUT_ITEM_FILE,
                                        func_name=function_name,
                                        runtime=LAMBDA_RUNTIME_PYTHON36)
        data = {
            short_uid(): 'data-{}'.format(i)
            for i in range(3)
        }
        event = {
            'table_name': table_name,
            'region_name': config.DEFAULT_REGION,
            'items': [{'id': k, 'data': v} for k, v in data.items()]
        }
        self.lambda_client.invoke(
            FunctionName=function_name,
            Payload=json.dumps(event)
        )
        dynamodb = aws_stack.connect_to_resource('dynamodb')
        rs = dynamodb.Table(table_name).scan()
        items = rs['Items']
        self.assertEqual(len(items), len(data.keys()))
        for item in items:
            self.assertEqual(data[item['id']], item['data'])
        
        testutil.delete_lambda_function(function_name)
        dynamodb_client = aws_stack.connect_to_service('dynamodb')
        dynamodb_client.delete_table(TableName=table_name)
    def test_lambda_start_stepfunctions_execution(self):
        function_name = '{}-{}'.format(TEST_LAMBDA_FUNCTION_PREFIX, short_uid())