Updated zenva free course

docs/en/en.json

@@ -634,7 +634,7 @@
                 "path": "https://academy.zenva.com/course/defold-101/",
                 "name": "Defold 101 – Open-Source Game Development",
                 "description": "In this course, you’ll dive into Defold, master how it works from scratch, and also explore essential fundamentals with the Lua scripting language. These skills will provide you the boost you need to start working with Defold in general and prepare you with the foundations for any sort of game you wish to build.",
-                "image": "/courses/images/zenva.png",
+                "image": "/courses/images/zenva-free.png",
                 "author": "Zenva"
             },
             {