[RELEASE] Released version 2.3-dev0

Released version 2.3-dev0 with the following main changes :
    - exact copy of 2.2.0
diff --git a/doc/management.txt b/doc/management.txt
index 0585d38..7346d63 100644
--- a/doc/management.txt
+++ b/doc/management.txt
@@ -1,7 +1,7 @@
                              ------------------------
                              HAProxy Management Guide
                              ------------------------
-                                   version 2.2
+                                   version 2.3
 
 
 This document describes how to start, stop, manage, and troubleshoot HAProxy,