Update learn.json

Author: alesanchezr

learn.json

@@ -10,7 +10,7 @@
 },
 "repository": "https://github.com/4GeeksAcademy/bootstrap-exercises-tutorial",
 "language": "html",
-"duration": 8,
+"duration": 5,
 "preview": "https://github.com/4GeeksAcademy/bootstrap-exercises-tutorial/blob/master/preview.png?raw=true",
 "difficulty": "easy",
 "skills": ["bootstrap", "html-layouts", "css-styling"],
@@ -26,4 +26,4 @@
     "version": "3.1.36"
 }
 
-}
+}