Fix for favicon route when app not in web root

Author: abejenaru

src/helpers.php

@@ -6,7 +6,7 @@
     function favicon($image)
     {
         if (app(FaviconGenerator::class)->shouldGenerateFavicon(app()->environment())) {
-            return '/'.config('favicon.url_prefix')."/$image";
+            return rtrim(config('app.url'), '/').'/'.config('favicon.url_prefix')."/$image";
         }
 
         return $image;