Fix sitemap to include all pages using .Site.AllPages

Author: Debdyut

portfolio/layouts/_default/sitemap.xml

@@ -1,7 +1,7 @@
 {{ printf "<?xml version=\"1.0\" encoding=\"utf-8\" standalone=\"yes\"?>" | safeHTML }}
 <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
   xmlns:xhtml="http://www.w3.org/1999/xhtml">
-{{ range .Data.Pages }}
+{{ range .Site.AllPages }}
   <url>
     <loc>{{ .Permalink }}</loc>{{ if not .Lastmod.IsZero }}
     <lastmod>{{ safeHTML ( .Lastmod.Format "2006-01-02T15:04:05-07:00" ) }}</lastmod>{{ end }}{{ with .Sitemap.ChangeFreq }}