Update off-canvas.html

Changed the google url to https. This fixes mixed content warnings in your browser for sites that have valid SSL certificates.

layouts/partials/off-canvas.html

@@ -19,7 +19,7 @@ <h6>{{ . }}</h6>
         {{ end }}
 
         <div>
-            <form name="google-search" method="get" action="http://www.google.com/search" target="_blank">
+            <form name="google-search" method="get" action="https://www.google.com/search" target="_blank">
                 <input type="hidden" name="sitesearch" value="{{ .Site.BaseURL }}" />
                 <input name="q" type="text" />
                 <input type="submit" name="sa" value="Google" />