refactor: ♻️ use custom sitemap generation instead of package

src/sitemap.njk

@@ -1,6 +1,16 @@
 ---
 permalink: /sitemap.xml
-layout: null
 eleventyExcludeFromCollections: true
 ---
-{# {% sitemap collections.all %} #}
+<?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 | isoDate }}</lastmod>
+        <changefreq>{{ page.data.changeFreq if page.data.changeFreq else "monthly" }}</changefreq>
+      </url>
+    {% endif %}
+  {% endfor %}
+</urlset>