Update the link to OpenAPI in the documentation (#1379)

Author: jbonofre

site/content/in-dev/0.9.0/rest-catalog-open-api.md

@@ -24,4 +24,4 @@ params:
   show_page_toc: false
 ---
 
-{{< redoc-polaris "rest-catalog-open-api.yaml" >}}
+{{< redoc-polaris "https://raw.githubusercontent.com/apache/polaris/refs/tags/apache-polaris-0.9.0-incubating/spec/rest-catalog-open-api.yaml" >}}