fix broken link (#1950)

docs/source/deployment/airflow_astronomer.md

@@ -12,7 +12,7 @@ The general strategy to deploy a Kedro pipeline on Apache Airflow is to run ever
 
 To follow this tutorial, ensure you have the following:
 
-* An Airflow cluster: you can follow [Astronomer's quickstart guide](https://docs.astronomer.io/astro/#get-started) to set one up.
+* An Airflow cluster: you can follow [Astronomer's quickstart guide](https://docs.astronomer.io/astro/category/install-astro) to set one up.
 * The [Astro CLI installed](https://docs.astronomer.io/astro/install-cli)
 * `kedro>=0.17` installed