Simple share image replacement (#545)

Author: palewire

_includes/head.html

@@ -8,7 +8,7 @@
     <meta property="og:title" content="Project Jupyter" />
     <meta property="og:description" content="{{ site.description|strip_html }}">
     <meta property="og:url" content="{{ site.url }}" />
-    <meta property="og:image" content="{{ "/assets/homepage.png" | prepend: site.url }}" />
+    <meta property="og:image" content="{{ "/assets/share.png" | prepend: site.url }}" />
     <link rel="canonical" href="{{ page.url | replace:'index.html','' | prepend: site.baseurl | prepend: site.url }}">
     <link rel="stylesheet" href="{{ "/assets/css/bootstrap.css" | prepend: site.baseurl }}">
     <link rel="stylesheet" href="{{ "/assets/css/main.css" | prepend: site.baseurl }}">