docs: update atlantis ref link on infracost.io (#4289)

Signed-off-by: Rui Chen <[email protected]>

runatlantis.io/docs/post-workflow-hooks.md

@@ -42,7 +42,7 @@ You can add a post workflow hook to perform custom reporting after all workflows
 have finished.
 
 In this example we use a custom workflow to generate cost estimates for each
-workflow using [Infracost](https://www.infracost.io/docs/integrations/atlantis/), then create a summary report after all workflows have completed.
+workflow using [Infracost](https://www.infracost.io/docs/integrations/cicd/#cicd-integrations), then create a summary report after all workflows have completed.
 
 
 ```yaml