update font awesome

Author: jessesquires

_includes/head.html

@@ -21,7 +21,7 @@
         integrity="sha384-BVYiiSIFeK1dGmJRAkycuHAHRg32OmUcww7on3RYdg4Va+PmSTsz/K68vbdEjh4u"
         crossorigin="anonymous">
 
-    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.3/css/font-awesome.min.css">
+    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css">
 
     <link href="/css/syntax.css" rel="stylesheet">
     <link href="/css/style.css" rel="stylesheet">