Updated feed.xml

I'm not sure but you guys are using the `jekyll-feed` plugin right?
According to my searches, it is outdated... https://github.com/jekyll/jekyll-feed
Here it is the updated version: https://github.com/jekyll/jekyll-feed/blob/master/lib/jekyll-feed/feed.xml
(included in the code above)

feed.xml

@@ -1,30 +1,84 @@
 ---
 layout: null
 ---
-<?xml version="1.0" encoding="UTF-8"?>
-<rss version="2.0" xmlns:atom="http://www.w3.org/2005/Atom">
-  <channel>
-    <title>{{ site.title | xml_escape }}</title>
-    <description>{{ site.description | xml_escape }}</description>
-    <link>{{ site.url }}/</link>
-    <atom:link href="{{ "/feed.xml" }}" rel="self" type="application/rss+xml" />
-    <pubDate>{{ site.time | date_to_rfc822 }}</pubDate>
-    <lastBuildDate>{{ site.time | date_to_rfc822 }}</lastBuildDate>
-    <generator>Jekyll v{{ jekyll.version }}</generator>
-    {% for post in site.posts limit:10 %}
-      <item>
-        <title>{{ post.title | xml_escape }}</title>
-        <description>{{ post.description | xml_escape }}</description>
-        <pubDate>{{ post.date | date_to_rfc822 }}</pubDate>
-        <link>{{ post.url | prepend: site.url }}</link>
-        <guid isPermaLink="true">{{ post.url | prepend: site.url }}</guid>
+<?xml version="1.0" encoding="utf-8"?>
+{% if page.xsl %}
+  <?xml-stylesheet type="text/xml" href="{{ '/feed.xslt.xml' | absolute_url }}"?>
+{% endif %}
+<feed xmlns="http://www.w3.org/2005/Atom" {% if site.lang %}xml:lang="{{ site.lang }}"{% endif %}>
+  <generator uri="https://jekyllrb.com/" version="{{ jekyll.version }}">Jekyll</generator>
+  <link href="{{ page.url | absolute_url }}" rel="self" type="application/atom+xml" />
+  <link href="{{ '/' | absolute_url }}" rel="alternate" type="text/html" {% if site.lang %}hreflang="{{ site.lang }}" {% endif %}/>
+  <updated>{{ site.time | date_to_xmlschema }}</updated>
+  <id>{{ '/' | absolute_url | xml_escape }}</id>
+
+  {% if site.title %}
+    <title type="html">{{ site.title | smartify | xml_escape }}</title>
+  {% elsif site.name %}
+    <title type="html">{{ site.name | smartify | xml_escape }}</title>
+  {% endif %}
+
+  {% if site.description %}
+    <subtitle>{{ site.description | xml_escape }}</subtitle>
+  {% endif %}
+
+  {% if site.author %}
+    <author>
+        <name>{{ site.author.name | default: site.author | xml_escape }}</name>
+      {% if site.author.email %}
+        <email>{{ site.author.email | xml_escape }}</email>
+      {% endif %}
+      {% if site.author.uri %}
+        <uri>{{ site.author.uri | xml_escape }}</uri>
+      {% endif %}
+    </author>
+  {% endif %}
+
+  {% assign posts = site.posts | where_exp: "post", "post.draft != true" %}
+  {% for post in posts limit: 10 %}
+    <entry{% if post.lang %}{{" "}}xml:lang="{{ post.lang }}"{% endif %}>
+      <title type="html">{{ post.title | smartify | strip_html | normalize_whitespace | xml_escape }}</title>
+      <link href="{{ post.url | absolute_url }}" rel="alternate" type="text/html" title="{{ post.title | xml_escape }}" />
+      <published>{{ post.date | date_to_xmlschema }}</published>
+      <updated>{{ post.last_modified_at | default: post.date | date_to_xmlschema }}</updated>
+      <id>{{ post.id | absolute_url | xml_escape }}</id>
+      <content type="html" xml:base="{{ post.url | absolute_url | xml_escape }}">{{ post.content | strip | xml_escape }}</content>
+
+      {% assign post_author = post.author | default: post.authors[0] | default: site.author %}
+      {% assign post_author = site.data.authors[post_author] | default: post_author %}
+      {% assign post_author_email = post_author.email | default: nil %}
+      {% assign post_author_uri = post_author.uri | default: nil %}
+      {% assign post_author_name = post_author.name | default: post_author %}
+
+      <author>
+          <name>{{ post_author_name | default: "" | xml_escape }}</name>
+        {% if post_author_email %}
+          <email>{{ post_author_email | xml_escape }}</email>
+        {% endif %}
+        {% if post_author_uri %}
+          <uri>{{ post_author_uri | xml_escape }}</uri>
+        {% endif %}
+      </author>
+
+      {% if post.category %}
+        <category term="{{ post.category | xml_escape }}" />
+      {% endif %}
+
       {% for tag in post.tags %}
-        <category>{{ tag | xml_escape }}</category>
+        <category term="{{ tag | xml_escape }}" />
       {% endfor %}
-        {% for cat in post.categories %}
-        <category>{{ cat | xml_escape }}</category>
+
+      {% if post.excerpt and post.excerpt != empty %}
+        <summary type="html">{{ post.excerpt | strip_html | normalize_whitespace | xml_escape }}</summary>
+      {% endif %}
+
+      {% assign post_image = post.image.path | default: post.image %}
+      {% if post_image %}
+        {% unless post_image contains "://" %}
+          {% assign post_image = post_image | absolute_url | xml_escape  %}
+        {% endunless %}
+        <media:thumbnail xmlns:media="http://search.yahoo.com/mrss/" url="{{ post_image }}" />
+      {% endif %}
+    </entry>
   {% endfor %}
-      </item>
-    {% endfor %}
-  </channel>
-</rss>
+</feed>