Update header.html

Author: danielbachhuber

_includes/header.html

@@ -5,7 +5,7 @@
 		<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1">
 		<meta name="viewport" content="width=device-width, initial-scale=1">
 		<link href='https://fonts.googleapis.com/css?family=Open+Sans:400,300,600,400italic' rel='stylesheet' type='text/css'>
-		<link rel="stylesheet" type="text/css" href="/assets/css/stylesheet.css?v=2" media="screen" />
+		<link rel="stylesheet" type="text/css" href="/assets/css/stylesheet.css?v=3" media="screen" />
 		<link rel="stylesheet" type="text/css" href="/assets/css/fa.css" media="screen" />
 
 		<link rel="icon" type="image/x-icon" href="/assets/img/favicon.ico" />