Documentation/integrations.md: Add aioetcd3 to Python language bindings
aioetcd3 is a Python binding for etcdv3 API for asyncio.
- [lisael/aioetcd](https://github.com/lisael/aioetcd) - (Python 3.4+) Asyncio coroutines client (Supports v2)
- [txaio-etcd](https://github.com/crossbario/txaio-etcd) - Asynchronous etcd v3-only client library for Twisted (today) and asyncio (future)
- [dims/etcd3-gateway](https://github.com/dims/etcd3-gateway) - etcd v3 API library using the HTTP grpc gateway
+- [aioetcd3](https://github.com/gaopeiliang/aioetcd3) - (Python 3.6+) etcd v3 API for asyncio
**Node libraries**
