docs: fix valkey doc broken link (googleapis#916)

In
[genai-toolbox](https://googleapis.github.io/genai-toolbox/resources/sources/valkey/)
Official Documentation of valkey URL is broken.

---------

Co-authored-by: Yuan Teoh <[email protected]>

Author: 2 people

docs/en/resources/sources/valkey.md

@@ -17,7 +17,7 @@ sets, sorted sets with range queries, bitmaps, hyperloglogs, and geospatial
 indexes with radius queries.
 
 If you're new to Valkey, you can find installation and getting started guides on
-the [official Valkey website](https://valkey.io/docs/getting-started/).
+the [official Valkey website](https://valkey.io/topics/quickstart/).
 
 ## Example