fixed run recipe command

Author: rswamina

_episodes/04-recipe.md

@@ -36,7 +36,7 @@ We will start by running [examples/recipe_python.yml](https://docs.esmvaltool.
 org/en/latest/recipes/recipe_examples.html)
 
 ```
-esmvaltool run recipe_python.yml
+esmvaltool run examples/recipe_python.yml
 ```