Update url of css files.

Author: yanglr

_includes/head.html

@@ -206,15 +206,15 @@
 
     <!-- Third-Party CSS -->
     <link rel="stylesheet" href="//cdn.jsdelivr.net/gh/yanglr/yanglr.github.io/bower_components/bootstrap/dist/css/bootstrap.min.css">
-    <link rel="stylesheet" href="//geekzl.com/bower_components/octicons/octicons/octicons.css">
+    <link rel="stylesheet" href="https://geekzl.com/bower_components/octicons/octicons/octicons.css">
     <link rel="stylesheet" href="//cdn.jsdelivr.net/gh/yanglr/yanglr.github.io/bower_components/hover/css/hover-min.css">
     <link rel="stylesheet" href="//cdn.jsdelivr.net/gh/yanglr/yanglr.github.io/bower_components/primer-markdown/dist/user-content.min.css">
-    <link rel="stylesheet" href="//geekzl.com/assets/css/syntax.css">
-	<link rel="stylesheet" href="//geekzl.com/assets/css/sidebar-post-nav.css">
+    <link rel="stylesheet" href="https://geekzl.com/assets/css/syntax.css">
+	<link rel="stylesheet" href="https://geekzl.com/assets/css/sidebar-post-nav.css">
 	<link rel="stylesheet" href="https://cdn.jsdelivr.net/gh/yanglr/yanglr.github.io@master/assets/vendor/share.js/dist/css/share.min.css">
 
     <!-- My CSS -->
-    <link rel="stylesheet" href="//geekzl.com/assets/css/common.css">
+    <link rel="stylesheet" href="https://geekzl.com/assets/css/common.css">
 
     <!-- CSS set in page -->
     {% for css in page.css %}