Merge #648: annoucements: Mention bitcoin-core-dev mailing list

fb9acf7 annoucements: Mention bitcoin-core-dev mailing list (MarcoFalke)

Pull request description:

ACKs for top commit:
  harding:
    Tested ACK fb9acf7 Thanks!

Tree-SHA512: de907b8687999047d0045e67ce8e402c448657bb3df340be5d834e541995e237d3a7fc5e52071686022f8767df05c84c59518e8caaf1c74b7b309ceaba6c0d4d

_posts/en/pages/list/2016-03-10-announcements-join.md

@@ -5,12 +5,14 @@ permalink: /en/list/announcements/join/
 type: pages
 layout: page
 lang: en
-version: 2
+version: 3
 ---
 Receive notification of important security announcements and releases for Bitcoin Core.
 
-Subscribe to the RSS feed below.
+Subscribe to the RSS feed below or add your email address to the [bitcoin-core-dev][] mailing list.
 
 {% include pages/list/announcement.html %}
 
 Low traffic for announcements only.
+
+{% include references.md %}