Fix sitemap.xml (#91)

- Remove invalid homepage widget links generated by Hugo

layouts/sitemap.xml

@@ -0,0 +1,13 @@
+<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+  {{ range (where .Data.Pages "Section" "!=" "home") }}
+    {{ $perm := add $.Site.LanguagePrefix "/home/" }}
+    {{ if ne .RelPermalink $perm }}
+    <url>
+      <loc>{{ .Permalink }}</loc>{{ if not .Lastmod.IsZero }}
+      <lastmod>{{ safeHTML ( .Lastmod.Format "2006-01-02T15:04:05-07:00" ) }}</lastmod>{{ end }}{{ with .Sitemap.ChangeFreq }}
+      <changefreq>{{ . }}</changefreq>{{ end }}{{ if ge .Sitemap.Priority 0.0 }}
+      <priority>{{ .Sitemap.Priority }}</priority>{{ end }}
+    </url>
+    {{ end }}
+  {{ end }}
+</urlset>