Increase RSS feed to 50 last entries

Also update property name to latest from jekyll-feed

Receiving only the last 10 is detremental for people
only occasionally fetching RSS feeds through their reader.
We could go infinite but 50 bring up back 6 months in the past
that is a good start.

Author: emmanuelbernard

_config.yml

@@ -239,3 +239,5 @@ jekyll-archives:
 
 
 ############################################################
+feed:
+  posts_limit: 50

feed.xml

@@ -10,7 +10,8 @@ layout: null
         <link>{{ site.url }}</link>
         <description>{{ site.description | xml_escape }}</description>
         <lastBuildDate>{{ site.time | date_to_rfc822 }}</lastBuildDate>
-        {% for post in site.posts limit:10 %}
+        {% assign posts_limit = site.feed.posts_limit | default: 10 %}
+        {% for post in site.posts limit: posts_limit %}
         <item>
             <title>{{ post.title | xml_escape }}</title>
             <link>