Update Font Awesome (mmistakes#2102)

REF: https://github.com/FortAwesome/Font-Awesome/blob/master/CHANGELOG.md

Author: coliff

_includes/scripts.html

@@ -9,7 +9,7 @@
   {% endfor %}
 {% else %}
   <script src="{{ '/assets/js/main.min.js' | relative_url }}"></script>
-  <script defer src="https://use.fontawesome.com/releases/v5.7.1/js/all.js" integrity="sha384-eVEQC9zshBn0rFj4+TU78eNA19HMNigMviK/PU/FFjLXqa/GKPgX58rvt5Z8PLs7" crossorigin="anonymous"></script>
+  <script defer src="https://use.fontawesome.com/releases/v5.8.1/js/all.js" integrity="sha384-g5uSoOSBd7KkhAMlnQILrecXvzst9TdC09/VM+pjDTCM+1il8RHz5fKANTFFb+gQ" crossorigin="anonymous"></script>
 {% endif %}
 
 {% if site.search == true or page.layout == "search" %}