docs: Fix broken link to introduction blog (#5319)

Signed-off-by: jmjf <jamee.mikell@gmail.com>

docs/getting-started.md

@@ -122,7 +122,7 @@ See up to date [jsonnet mixins](https://github.com/thanos-io/thanos/tree/main/mi
 
 * 2018:
 
-  * [Introduction blog post](https://improbable.io/games/blog/thanos-prometheus-at-scale)
+  * [Introduction blog post](https://improbable.io/blog/thanos-prometheus-at-scale)
   * [Monzo user story](https://monzo.com/blog/2018/07/27/how-we-monitor-monzo)
   * [Banzai Cloud hand's on](https://banzaicloud.com/blog/hands-on-thanos/)
   * [uSwitch user story](https://medium.com/uswitch-labs/making-prometheus-more-awesome-with-thanos-fbec8c6c28ad)