preconnect to required origins and minifies subscribe.css

Signed-off-by: shubhusion <[email protected]>

Author: shubhusion

_includes/header.html

@@ -5,8 +5,9 @@
     <meta charset="utf-8" />
     <meta name="viewport" content="width=device-width, initial-scale=1" />
 
+    <link rel="dns-prefetch" href="//www.googletagmanager.com">
     <!-- Google Tag Manager -->
-    <script>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
+    <script defer>(function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':
     new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],
     j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src=
    'https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);
@@ -20,6 +21,8 @@
     {% endif %}
     <link rel="stylesheet" href="{{ site.baseurl }}/css/screen.css" />
     <link rel="icon" type="image/png" href="{{ site.baseurl }}/favicon.ico" />
+    <link rel="dns-prefetch" href="//fonts.googleapis.com">
+    <link rel="dns-prefetch" href="//cdnjs.cloudflare.com">
     <link
       rel="stylesheet"
       href="https://fonts.googleapis.com/css?family=Open+Sans"