Per invocation log docs (#60)

* Per invocation log docs

* Update apps/logs.mdx

Co-authored-by: Catherine Jue <[email protected]>

---------

Co-authored-by: Catherine Jue <[email protected]>

Author: hiroTamada

apps/logs.mdx

@@ -34,3 +34,8 @@ kernel logs <app_name> --follow
 ```
 
 If you don't specify `--follow`, the logs will print to the terminal until 3 seconds of inactivity and then stops.
+
+You can get logs for a specific invocation by adding:
+```
+-i --invocation <invocation id>    Show logs for a specific invocation of the app.
+```