docs: fix installation version of packages (#8177)

www/apps/resources/app/architectural-modules/workflow-engine/redis/page.mdx

@@ -21,7 +21,7 @@ The Redis Workflow Engine Module uses Redis to track workflow executions and han
 To install Redis Workflow Engine Module, run the following command in the directory of your Medusa application:
 
 ```bash npm2yarn
-npm install @medusajs/workflow-engine-redis
+npm install @medusajs/workflow-engine-redis@preview
 ```
 
 Next, add the module into the `modules` property of the exported object in `medusa-config.js`: