Update aio-pika external docs URL as it has been moved (#1984)

https://aio-pika.readthedocs.io/ currently returns 404 Project not found and it appears the documentation is now hosted at https://docs.aio-pika.com/

docs/docs/en/rabbit/index.md

@@ -11,7 +11,7 @@ search:
 # Rabbit Routing
 
 !!! note ""
-      **FastStream** *RabbitMQ* support is implemented on top of [**aio-pika**](https://aio-pika.readthedocs.io/en/latest/){.external-link target="_blank"}. You can always get access to objects of it, if you need to use some low-level methods, not represented in **FastStream**.
+      **FastStream** *RabbitMQ* support is implemented on top of [**aio-pika**](https://docs.aio-pika.com/){.external-link target="_blank"}. You can always get access to objects of it, if you need to use some low-level methods, not represented in **FastStream**.
 
 ## Advantages