Update logo to not use HTTP, but also allows HTTPS

_layouts/index.html

@@ -11,7 +11,7 @@
       <header class="hero-header">
         <div class="pagewidth">
           <div class="logo--ie">
-            <img src="http://shopify.github.io/images/shopify-open-source-sub.svg" alt="Shopify Open Source" class="logo">
+            <img src="//shopify.github.io/images/shopify-open-source-sub.svg" alt="Shopify Open Source" class="logo">
             <span class="breadcrumb"><a href="http://shopify.github.io">Open Source</a> > {{ site.github.project_title }}</span>
           </div>
           <div class="repo-lang {{ site.github.language | downcase }}">