Update favicon text to png

Author: devalog

_includes/head.html

@@ -4,7 +4,7 @@
   <meta name="viewport" content="width=device-width, initial-scale=1">
   {%- seo -%}
   <link rel="stylesheet" href="{{ "/assets/main.css" | relative_url }}">
-  <link rel="icon" type="image/jpeg" href="{{ '/favicon.jpg' | relative_url }}">
+  <link rel="icon" type="image/png" href="{{ '/favicon.png' | relative_url }}">
   {%- feed_meta -%}
   {%- if jekyll.environment == 'production' and site.google_analytics -%}
     {%- include google-analytics.html -%}