Add xml declaration to sitemap

src/sitemap.html

@@ -2,12 +2,15 @@
 permalink: /sitemap.xml
 eleventyExcludeFromCollections: true
 ---
+<?xml version="1.0" encoding="utf-8"?>
 <urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
     {% for page in collections.all %}
+       {% if not page.data.draft %}
         <url>
             <loc>{{ site.url }}{{ page.url | url }}</loc>
             <lastmod>{{ page.date }}</lastmod>
             <changefreq>{{page.data.changeFreq}}</changefreq>
         </url>
+       {% endif %}
     {% endfor %}
 </urlset>