Merge pull request #195 from ESMValGroup/fix_link_to_recipe_file

Fixed broken link to example recipe in lesson 4

Author: Peter9192

_episodes/04-recipe.md

@@ -29,7 +29,7 @@ recipes that are shipped with ESMValTool, type
 esmvaltool recipes list
 ```
 
-We will start by running [examples/recipe_python.yml](https://docs.esmvaltool.org/en/latest/recipes/recipe_python.html)
+We will start by running [examples/recipe_python.yml](https://docs.esmvaltool.org/en/latest/recipes/recipe_examples.html)
 
 ```
 esmvaltool run examples/recipe_python.yml