update font_awesome cdn url

Author: Young-Lord

_data/variables.yml

@@ -42,7 +42,7 @@ default:
 
 sources:
   bootcdn:
-    font_awesome: 'https://cdn.bootcdn.net/ajax/libs/font-awesome/5.15.1/css/all.css'
+    font_awesome: 'https://cdn.bootcdn.net/ajax/libs/font-awesome/5.15.1/css/all.min.css'
     jquery: 'https://cdn.bootcss.com/jquery/3.1.1/jquery.min.js'
     leancloud_js_sdk: '//cdn.jsdelivr.net/npm/leancloud-storage@3.13.2/dist/av-min.js'
     chart: 'https://cdn.bootcss.com/Chart.js/2.7.2/Chart.bundle.min.js'