Fix feed

Author: quincylvania

_source/feed.xml

@@ -15,7 +15,7 @@
         <title>{{ item.title | xml_escape }}</title>
         <dc:creator>Quincy Morgan</dc:creator>
         <dc:rights>© {{ item.date | date: '%Y' }} Quincy Morgan</dc:rights>
-        {% if item.updated -%}<dcterms:modified>{{ item.updated | date: "%a, %d %b %Y %H:%M:%S %z" }}</dcterms:modified>{%- endif %}
+        {% if item.updated -%}<dcterms:modified>{{ item.updated | date: "%Y-%m-%dT%H:%M:%S%:z" }}</dcterms:modified>{%- endif %}
         <pubDate>{{ item.date | date: "%a, %d %b %Y %H:%M:%S %z" }}</pubDate>
         <link>{{ item.url | absolute_url }}</link>
         <guid isPermaLink="true">{{ item.url | absolute_url }}</guid>