Update Font Awesome to v5.7.1

Author: pascalandy

partials/custom_header.hbs

@@ -7,8 +7,8 @@
 <link rel="stylesheet" type="text/css" href="{{asset "css_firepress/simplegrid.min.css"}}" /> -->
 
 <!-- CSS Icon via fontawesome 5 -->
-<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.6.3/css/v4-shims.css">
-<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.6.3/css/all.css" integrity="sha384-UHRtZLI+pbxtHCWp1t77Bi1L4ZtiqrqD80Kn4Z8NTSRyMA2Fd33n5dQ8lWUE00s/" crossorigin="anonymous">
+<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.1/css/v4-shims.css">
+<link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.7.1/css/all.css" integrity="sha384-fnmOCqbTlWIlj8LyTjo7mOUStjsKC4pOpQbqyi7RrhN7udi9RwhKkMHpvLbHG9Sr" crossorigin="anonymous">
 
 <!-- CSS Code Syntax (highlight agate) -->
 <!-- Line number is not supported > http://highlightjs.readthedocs.io/en/latest/line-numbers.html -->