chore(docs): reference Swoole promise adapter

Author: mcharytoniuk

docs/complementary-tools.md

@@ -17,6 +17,7 @@
 - [GraphQL Batch Processor](https://github.com/vasily-kartashov/graphql-batch-processing) – Provides a builder interface for defining collection, querying, filtering, and post-processing logic of batched data fetches
 - [GraphQL Utils](https://github.com/simPod/GraphQL-Utils) – Objective schema definition builders (no need for arrays anymore)
 - [Relay Library](https://github.com/ivome/graphql-relay-php) – Helps construct Relay related schema definitions
+- [Resonance/GraphQL](https://resonance.distantmagic.com/docs/features/graphql/) – Integrates with Swoole for parallelism. Define your schema code-first with annotations.
 - [GraphQL PHP Validation Toolkit](https://github.com/shmax/graphql-php-validation-toolkit) - Small library for validation of user input
 
 * [MLL Scalars](https://github.com/mll-lab/graphql-php-scalars) - Collection of custom scalar types

docs/data-fetching.md

@@ -292,6 +292,9 @@ Where **$promiseAdapter** is an instance of:
 - For [AMPHP](https://github.com/amphp/amp): <br>
   `GraphQL\Executor\Promise\Adapter\AmpPromiseAdapter`
 
+- For [Swoole](https://swoole.com/) or [OpenSwoole](https://openswoole.com/): <br>
+    You can use an external library: [Resonance](https://resonance.distantmagic.com/docs/features/graphql/standalone-promise-adapter.html)
+
 - Other platforms: write your own class implementing interface: <br>
   [`GraphQL\Executor\Promise\PromiseAdapter`](class-reference.md#graphqlexecutorpromisepromiseadapter).