doc: use a protocol-indepedent link for video cover

Otherwise, we may get mixed-content warnings.
vincentbernat · Aug 7, 2015 · ff1f5ee · ff1f5ee
1 parent ef14cdc
commit ff1f5ee
Showing 1 changed file with 1 addition and 1 deletion.
diff --git a/README.md b/README.md
@@ -28,7 +28,7 @@ A live installation, reset every hour, is publicly available:
 
 Here is a demonstration video:
 
-[![Dashkiosk demo](http://img.youtube.com/vi/Vb4BvEzoYOU/0.jpg)](https://www.youtube.com/watch?v=Vb4BvEzoYOU "Dashkiosk demo")
+[![Dashkiosk demo](//img.youtube.com/vi/Vb4BvEzoYOU/0.jpg)](https://www.youtube.com/watch?v=Vb4BvEzoYOU "Dashkiosk demo")
 
 # Development